(n.b. that the OED says the entry hasn't been updated since 1900)

inspiration, n.

Etymology: Old French en-, inspiration, -cion (12-13th cent. in Hatzfeld & Darmesteter), Latin inspiration-em , noun of action from inspirare to inspire v.

I. Literal (physical) senses.

1.
The action of blowing on or into. Obsolete. rare.
1513 G. Douglas in tr. Virgil Æneid xii. Prol. 75 The sulȝe spred hyr braid bosum on breid, Zephyrus comfortabill inspiratioun For till ressaue.
1708 Ld. Shaftesbury Let. conc. Enthusiasm 43 Their strange Voices..are admirably well acted, by the..Inspiration of Pipes.

2.
a. The action, or an act, of breathing in or inhaling; the drawing in of the breath into the lungs in respiration. (Opposed to expiration n. 2.)
1564 W. Bullein Dialogue against Fever Pestilence f. 26v This is a dispersed pestilence, by the inspiracion of the ayre.
1607 E. Grimeston tr. S. Goulart Admirable & Memorable Hist. 440 That a Priest at Rome lived fortie yeares with the onely inspiration of the aire.
1650 J. Bulwer Anthropometamorphosis 79 The Nostrils serve for expiration and inspiration.
1753 N. Torriano tr. J. B. L. Chomel Hist. Diss. Gangrenous Sore Throat 124 A sore Throat, which she received by Inspiration of foul Air.
1774 O. Goldsmith Hist. Earth VII. 59 Upon going down he [sc. the diver] takes in a very long inspiration.
1849 Todd's Cycl. Anat. & Physiol. IV. ii. 1086/2 In Inspiration the lungs are passive.
1872 C. Darwin Expression Emotions Man & Animals xii. 284 We can draw a full and deep inspiration much more easily through the widely open mouth than through the nostrils.

b. transferred. A drawing in of air; the absorption of air in the 'respiration' of plants.
1785 T. Jefferson Notes Virginia v. 38 Regular inspirations and expirations of air, by caverns and fissures.
1838 T. Thomson Chem. Org. Bodies 1001 Plants will not live without this nightly inspiration, even though supplied with carbonic acid, provided the oxygen formed by them during the day be constantly withdrawn at the approach of night.

II. Figurative senses.
3. The action of inspiring; the fact or condition of being inspired (in sense 4a or 5a of inspire v.); a breathing or infusion into the mind or soul.

a. spec. (Theology, etc.) A special immediate action or influence of the Spirit of God (or of some divinity or supernatural being) upon the human mind or soul; said esp. of that divine influence under which the books of Scripture are held to have been written.Various views have been held as to the inspiration of Scripture, such as those of verbal inspiration, according to which every word written was dictated by the Spirit of God; plenary inspiration, according to which the inspiration of the writers extends to all subjects treated of, so that all their statements are to be received as infallibly true; moral inspiration, according to which the inspiration is confined to the moral and religious teaching imparted; dynamical inspiration, mechanical inspiration (see dynamical adj. 3).
1303 R. Mannyng Handlyng Synne 7746 þurghe grete þan ynspyracyun, He þoghte so on hys [Christ's] passyun.
a1340 R. Rolle Comm. on Canticles in Psalter xliv. 2 [xlv. 1] þe vertu of godis inspiracioun.
a1513 R. Fabyan New Cronycles Eng. & Fraunce (1516) I. cxix. f. lvii Seynt Augustyne..warnyd them by maner of Inspyracion, yt sene they wolde not receyue Peace of theyr Bretherne, they shuld of other receyue warre and wreche.
1526 W. Bonde Pylgrimage of Perfection iii. sig. DDDiii The inspiracions of the holy goste.
1526 Bible (Tyndale) 2 Tim. iii. 16 All scripture geven by inspiracion of god is proffitable to teache, to improve, to informe, and to instruct in rightewesnes.
1530 Myroure Oure Ladye (Fawkes) (1873) ii. 173 He sente the holy goste on Penthecoste sondaye to enspyracyon of hys dyscyples.
1532 (c1385) Usk's Test. Loue in Wks. G. Chaucer ii. f. cccxxxvi I thynke to perfourme this worke..as my thynne wytte, with inspyracion of hym that hyldeth al grace wol suffre.
1611 M. Smith in Bible (King James) Transl. Pref. 3 The Prophets, who teach us by diuine inspiration.
1692 R. South 12 Serm. I. 466 The..Principle..was certainly first..fetched up from the very bottom of Hell; and utter'd..by particular and immediate inspiration of the Devil.
1793 R. Hawker (title) Evidence of a Plenary Inspiration; a Letter to Mr. T. Porter, in Reply to his Defence of Unitarianism.
1841 Penny Cycl. XIX. 429/2 Theologians who hold the theory of plenary but not verbal inspiration.
1860 B. F. Westcott Introd. Study Gospels (ed. 5) App. B. 451 The early Fathers teach us that Inspiration is an operation of the Holy Spirit acting through men, according to the laws of their constitution.
1865 M. Arnold Ess. Crit. ix. 272 The noblest souls of whatever creed..have insisted on the necessity of an inspiration, a living emotion, to make moral action pefect.
1896 Duke of Argyll Philos. Belief 370 They warn us that there may be inspirations from below, as well as from above.

b. gen. A breathing in or infusion of some idea, purpose, etc. into the mind; the suggestion, awakening, or creation of some feeling or impulse, esp. of an exalted kind.
1651 T. Hobbes Leviathan ii. xxix. 169 Why any man should take the law of his country rather than his own Inspiration, for the rule of his action.
1692 tr. C. de Saint-Évremond Misc. Ess. 206 There are some Men, jealous of the Honour of their motions, who refuse all things at the Inspirations of others.
1769 'Junius' Stat Nominis Umbra (1772) I. vii. 48 The melancholy madness of poetry, without the inspiration.
1805 J. Foster Ess. i. ii. 27 A mind adapted and habituated to converse with the inspirations of nature.
1841 R. W. Emerson Love in Ess. 1st Ser. (London ed.) 177 Men have written good verses under the inspiration of passion, who cannot write well under any other circumstances.
1858 T. J. Hogg Life Shelley II. 416 Inspired with the soft inspiration of strong, sound ale.
1876 J. B. Mozley Univ. Serm. (1877) v. 108 There is inspiration in numbers, in men acting at once and together.

c. The suggestion or prompting (from some influential quarter) of the utterance or publication of particular views or information on some public matter. (Cf. inspire v. 7, inspired adj. 5.)
1880 Christian World No. 1195. 137 Correspondents..write in the interest, if not at the inspiration of the authorities.
1897 Daily News 13 Mar. 3/1 Mr. Goschen said it was not due to inspiration..No idea had been given to the journal.

4. transferred.

a. Something inspired or infused into the mind; an inspired utterance or product.
1819 Ld. Byron Proph. Dante iv. 2 Many are poets who have never penn'd Their inspiration.
1871 R. Ellis tr. Catullus Poems lxiv. 321 They..Pour'd grave inspiration, a prophet chant to the future.
1879 G. A. Sala in Daily Tel. 8 May Mr. G. F. Boughton's charming figure of 'Priscilla', an inspiration from Longfellow's 'Miles Standish'.

b. An inspiring principle.
1865 J. B. Mozley 8 Lect. Miracles vii. 146 To say that the inspiration of the missionary cause has been the belief in Christian doctrine is almost superfluous.
1869 J. B. Brown Misread Passages ix. 125 Christian charity, charity which has Christ for its model and inspiration.
1873 R. Browning Red Cotton Night-cap Country iv. 261 Whatever motive your own souls supply As inspiration.

5. In combinations.
1894 Nation (N.Y.) 23 Aug. 144/3 Inspiration-like insight.