impenetrable 
trabitis, penetrable: see penetrable.] 1. Inca- 
pable of being penetrated ; not penetrable, in 
any sense of that word. 
Highest woods, impenetrable 
To star or sun-light. Milton, P. L., ix. 1086. 
These instances of cunning, which she thought impene- 
trable, yet which everybody saw through. 
Goldsmith, Vicar, xvi. 
The progress of the most salutary inventions and dis- 
coveries is buried in impenetrable mystery. 
Macaulay, Mitford's Hist. Greece. 
2. Specifically, inpJiysicn, having the property 
of preventing any other substance from occu- 
pying the same place at the same time. 
impenetrableness (im-pen'e-tra-bl-nes), n. 
Impenetrability. 
We may consider that motion does not essentially be- 
long to matter, as divisibility and impenetrableness are be- 
lieved to do. Boyle, Works, V. 210. 
impenetrably (im-pen'e-tra-bli), adv. In an 
impenetrable manner ;' so "as to be impene- 
trable. 
The inviolable saints, 
In cubic phalanx firm, advanced entire, 
Invulnerable, impenetrably arm'd. 
Milton, P. L., vi. 400. 
impenitence (im-pen'i-teus), . [= F. impeni- 
tence = Sp. Pg. impenitencia = It. impenitenza, < 
LL. impoenitentia, inposnitentia, < imposniten(t-)s, 
!Hp<BHte(-)s, impenitent: see impenitent.] The 
condition of being impenitent ; want of peni- 
tence or repentance ; obduracy ; hardness of 
heart. 
He will advance from one degree of wickedness and im- 
penitence to another. Rogers. 
I thought you would not slay impenitence 
Teased first contrition from the man you slew 
I thought you had a conscience. 
Browning, Ring and Book, II. 299. 
impenitency (im-pen'i-teu-si), n. ; pi. impeni- 
tencies (-siz). Same as impenitence. 
What is this sin ? Final impenitency, and, some say, im- 
pugning of the truth. 
Latimer, 2d Sermon bef. Edw. VI., 1360. 
He undertook a grief great enough ... to satisfy for 
the impenitencies of all the world. 
Jer. Taylor, Works (ed. 1835), I. 318. 
impenitent (im-pen'i-tent), a. and . [= F. 
impenitent = Sp. Pg. It. impenitente, < LL. im- 
pceniten(t-)s, inpcmiten(t-)s, not penitent, < L. 
i-priv. + paeniten( t-)s, penitent : see penitent.] 
I. a. Not penitent; not repenting of sin; not 
contrite ; obdurate. 
I pity the flatteries and self applauses of a careless and 
impenitent heart. Bp. Hall, Soliloquies, xi. 
So died 
Impenitent, and left a race behind 
Like to themselves, distinguishable scarce 
rrom Gentiles. Milton, P. R., iii. 423. 
II. . One who does not repent; a hardened 
sinner. 
When the reward of penitents and punishment of im- 
peniteiits is once assented to as true, 'tis impossible but 
the mind of man should wish for the one, and have dis- 
likes to the other. Hammond. 
impenitently (im-pen'i-tent-li), adv. In an im- 
penitent manner; without repentance or con- 
trition for sin; obdurately. 
impenitiblet, [< L. in- priv. + pcenitere, re- 
pent, + -ible.] Incapable of repentance. 
As death works upon man, and concludes him, and makes 
him impenitible for ever, so works the fall upon the angels, 
and concludes them for ever too. Donne, Sermons, xxiv. 
impennate (im-pen'at), a. and n. [< L. in- priv. 
+ pennatus, winged : see pennate.] I. a. Fea- 
therless or wingless; specifically, character- 
ized by short wings covered with feathers re- 
sembling scales, as the penguins. 
II. n. A bird, as the penguin, with short wings 
covered with scales. 
Impennes (im-pen'ez), n. pi. [NL., < L. in- 
pnv. + peiina, a wing.] A group of birds, the 
penguins. Also called Spiieniscidai and Sphenis- 
apterous. 
It is generally conceived an earwig hath no wings, and 
is reckoned amongst impennous insects by many. 
Sir T. Browne, Vulg. Err., iii. 27. 
impeoplet (im-pe'pl), r. t. [< j-2 + people.] 
Same as empeople. 
Thick were the Walls impeopled with the stories 
Of those whom Chastity had clothed in White. 
J. Beaumont, Psyche, iii. 44. 
imper. An abbreviation of imperative. 
imperancet (im'pe-rans), . [< ML. "imperan- 
tia, < L. imi>emre, inperare, command : see im- 
perate.] Command; mastery. HalJiteett. 
3006 
imperantt (.im'pe-rant), a. [= Sp. Pg. impe- 
rante, < L. impi'ran(t-)s, inperan(t-)s, ppr. of 
imperare, inperare, command: see imperatc.] 
Commanding. 
imperate (im'pe-rat), a. [< L. imperatus. in- 
peratits, pp. of imperare, inperare, command, or- 
der, enjoin, < in, in, on, + pararc. make ready, 
order: see pare. Cf. empire.] Performed by a 
faculty other than the will, at the command of 
the will : opposed to elicit. 
I see the energy of my soul in every particle of my body, 
though not using intellectual actions in every part, yet 
using some that are imperate. 
Sir M. Hale, Orig. of Mankind, p. 22. 
Imperate act. See act. 
imperative (im-per-a-t!'ve), n. pi. [NL., fern, 
pi. (so.ferice, feasts) of imperative, imperative : 
see imperative.] In Bom. antiq., special or ex- 
traordinary feasts or holidays. See ferice. 
imperatival (im-per-a-ti'val or im-per'a-ti- 
val), . [< imperative + -al.] In gram., be- 
longing or peculiar to the imperative mode. 
imperative (im-per'a-tiv), a. and n. [= D. im- 
peratief = G. Dan. Sw. imperativ, the impera- 
tive mode, = F. imperatif= Sp. Pg. It. impera- 
tive, < L. imperativus, inperativus, of a command, 
imperative (as a noun, se. modus, the imperative 
mode), < imperare, inperare, command, order: 
see imperate.] I. a. 1. Expressing command; 
containing positive command; peremptory; 
absolute: as, imperative orders. 
The suits of kings are imperative. 
Bp. Hall, David with Bathshcba and Uriah. 
2. Not to be avoided or evaded ; that must be 
attended to or performed ; obligatory; binding: 
as, an imperative duty or necessity. 
The priest who needs must carry sword on thigh 
May find imperative use for it. 
Brouminy, Ring and Book, I. 319. 
Imperative mode, the mode or form or set of forms 
of a verb which express command, entreaty, advice, or ex- 
hortation: as, come here; restrain yourself; be comforted. 
= Syn. 1 and 2. Imperious, Imperative (see imperious\ 
absolute, express, positive, decided, not to be gainsaid. 
II. n. 1. In</r/.,amodeorverbalformwhich 
expresses command, entreaty, advice, or exhor- 
tation. 2. In philos., a deliverance of con- 
science ; a monition of the moral sense. 
By imperative, in general, every proposition that ex- 
presses a possible free action, by which a certain end is 
to be realized, is to be understood. 
Kant, tr. by Richardson. 
Such precepts are merely, what Kant calls them, Hy- 
pothetical Imperatives ; they are not addressed to any one 
who has not first accepted the end. 
H. Sidywick, Methods of Ethics, p. 7. 
But when the instruction has been conveyed, the self- 
imposed imperative to turn it to account for the better- 
ing of life remains to be given : and it is only from a 
conscience responsive to an ideal of virtue that it can 
proceed. T. B. Green, Prolegomena to Ethics, 307. 
Categorical Imperative. See categorical. 
imperatively (im-per'a-tiv-li), adv. 1. In an 
imperative manner ; peremptorily. 2. Byway 
or in the manner of the imperative mode, 
imperativeness (im-per'a-tiv-nes), n. The 
character of being imperative or obligatory; 
absolute requirement. 
All the animal functions, in common with the higher 
functions, have . . . their imperativeness. 
H. Spencer, Data of Ethics, p. 76. 
Neither [theory] explains the imperativeness with which 
recognized moral law speaks to the human heart. 
Pop. Sci. Mo., XXXIII. 418. 
imperator (im'pe-ra-tor), .. [L., also inpera- 
tor, OL. induperator, endoperator, a command- 
er, emperor, < imperare, inperare, command: 
see imperate. Hence ult. E. emperor.] 1. In 
Bom. hist. : (a) In general, a commander, chief, 
or ruler: in this sense a descriptive title (placed 
after the name) of any one possessing the im- 
perium or power of enforcing his authority, as 
a general, or a consul, proconsul, or other ma- 
gistrate. (&) In later times, more especially, 
a general-in-chief or holder of an independent 
command during active service : a title" often 
conferred by the senate on a victorious gen- 
eral, or acclaimed by his army. 
The powers of the imperator or commander of the Ro- 
man army ceased on his return to the city. 
Encyc. Brit., III. 80. 
(c) After the fall of the republic, the official 
title (used as a prenomen) of the monarch or 
supreme ruler as permanent generalissimo of 
the Roman armies ; emperor : originally con- 
ferred by the senate for a term, and afterward 
assumed in perpetuity. 
This senior-junior, giant-dwarf, Dan Cupid, . . . 
Sole imperator, and great general 
Of trotting paritors. Shak., L. L. L, iii. 1. 
Imperator tmperialis. 
imperceptible 
2. [cop.] In o67., a genus of trochiform pro- 
sobranchiate gastropods, of the family Turbi- 
iiiilie. Montfort. 
Imperatoria (im- 
per-a-td'ri-a), . 
[NL", fern:' of L. 
imiieratorius, of or 
belonging to a 
general or com- 
mander: see impe- 
ratory.] A genus 
of plants, of the 
natural order Um- 
belliferce, now usu- 
ally regarded as 
a section of Peucedanum. I. Ostruthium, the great 
masterwort, grows in moist pastures in various parts of 
Scotland, and was formerly much cultivated as a pot-herb. 
The root yields the vegetable resin imperatorin. 
imperatorial (im-per-a-to'ri-al), a. [As impera- 
tory + -al.] 1. Of or pertaining to the title 
or office of imperator or emperor: as, "impera- 
torial laurels," C. Merivale. 2. Like an im- 
perator; of a commanding nature or quality; 
imperial. 
Moses delivered this law after an imperatorial way, by 
saying, thou shalt do this, and thou shalt not do that 
If orris, The Beatitudes, p. 239. 
The imperatorial character of the language itself [Latin] 
PIC speech of masters, not of men. 
G. P. Marsh, Lects. on Eng. Lang., iv. 
Also imperatory. 
imperatorian (im-per-a-to'ri-an), a. [As im- 
peratory + -an.] Imperatorial. [Rare.] 
He professed not to meddle by atiy Imperatorian or 
Senatorian power with matters of Religion. 
Bp. Gauden, Tears of the Church, p. 143. 
imperatorin (im-per'a-to-rin), . [< Impera- 
toria + -in 2 .] A vegetable resin found in the 
root of Imperatoria Ostruthium, or great master- 
wort. It forms long transparent prisms, has an acrid 
burning taste, and is neutral, fusible, and soluble in alco- 
hol and ether. 
LmperatorioUSt (im-per-a-to'ri-us), a. [< L. 
imperatorius : see imperalory .] Same as im- 
peratorial. Dames. 
You have heard his Majesty's speech, though short, yet 
full and princely, and rightly imperatorious, as Tacitus 
said of Galba's. Bp. Hacket, Abp. Williams, ii. 9. 
imperatory (im-per'a-to-ri), a. [= F. impera- 
toire = Sp. Pg. It. impcr'atorio,< L. imperatorius, 
of or belonging to a general or commander, < 
imperator, ,a general: see impe-rator.] Same as 
imperatorial. 
All which stand 
In awe of thy high imperatory hand. 
Chapman, Hymn to Hermes. 
imperceivable (im-per-se'va-bl), a. [< -3 + 
perceivable.] Imperceptible. [Rare.] 
There is yet another way by which a temptation arrives 
to its highest pitch or proper hour ; and that is by a long 
train of gradual, imperceivable encroaches of the flesh 
upon the spirit South, Works, VI. vii. 
imperceivableness (im-per-se'va-bl-nes), n. 
Imperceptibleness. [Rare.] 
And this imperceivablenesg of the impressions made 
upon our souls by the Holy Spirit was that which our 
Saviour signified to Sicodemus, in the third of St John. 
Abp. Sharp, Works, III. v. 
imperceivedt (im-per-sevd'), a. [< in-3 + per- 
ceived.] Unperceived. 
Then finding the bladder to be pumped up, we would 
have tied up the contained air, but could not do it by 
reason of an imperceived hole. Boyle, Works, V. 620. 
imperceptibility (im-per-sep-ti-bil'i-ti), . [= 
F. imperceptibilite' = Sp. imperceptib'ilidad = Pg. 
imperceptibilidade = It. imperccttibilita ; as im- 
perceptible + -ity: see -bility.] The character 
or state of being imperceptible ; imperceptible- 
ness. Asli. 
imperceptible(im-per-sep'ti-bl),a.and n. [=F. 
imperceptible = Sp. imperceptible = Pg. impercep- 
tivel = It. impercettibile, < ML. imperceptibilis, 
not perceptible, < L. in- priv. + perceptibilis, 
perceptible.] I. a. Not perceptible ; that can- 
not be perceived, (a) Incapable by nature of affect- 
ing the senses. 
Seem'd washing his hands with invisible soap 
In imperceptible water. Howl, Miss Kilmansegg. 
(It) Too minute, fine, gradual, subtle, or evanescent to be 
discerned by the senses ; producing an excitation of the 
nerves less than the threshold of sensation. See threshold. 
Strange play of Fate ! when mightiest human things 
Hang on such small imperceptible things. 
Cowley, Davideis, iv. 
Its operation is slow, and in some cases almost imper- 
ceptible. Burke. 
The three-millionth part of a milligramme of a salt of 
Sodium, an imperceptible particle of dust to the naked 
eye, is yet capable of colouring the flame yellow, and of 
giving the yellow line of Sodium in the spectroscope. 
Lommel, Light (trans.), p. 152. 
