beast of burden, Old English assa (Old Northumbrian assal, assald) "he-ass," probably from Old Celtic *as(s)in "donkey," which (with German esel, Gothic asilus, Lithuanian asilas, Old Church Slavonic osl) ultimately is from Latin asinus, which is probably of Middle Eastern origin (cf. Sumerian ansu).
For al schal deie and al schal passe, Als wel a Leoun as an asse. [John Gower, "Confessio Amantis," 1393]Since ancient Greek times, in fables and parables, the animal typified clumsiness and stupidity (hence asshead, late 15c., etc.). To make an ass of oneself is from 1580s. Asses' Bridge (c.1780), from Latin Pons Asinorum, is fifth proposition of first book of Euclid's "Elements." In Middle English, someone uncomprehending or unappreciative would be lik an asse that listeth on a harpe. In 15c., an ass man was a donkey driver.
slang for "backside," first attested 1860 in nautical slang, in popular use from 1930; chiefly U.S.; from dialectal variant pronunciation of arse (q.v.). The loss of -r- before -s- attested in several other words (e.g. burst/bust, curse/cuss, horse/hoss, barse/bass). Indirect evidence of the change from arse to ass can be traced to 1785 (in euphemistic avoidance of ass "donkey" by polite speakers) and perhaps to Shakespeare, if Nick Bottom transformed into a donkey in "A Midsummer Night's Dream" (1594) is the word-play some think it is. Meaning "woman regarded as a sexual object" is from 1942. Colloquial (one's) ass "one's self, one's person" attested by 1958.
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frequently mentioned throughout Scripture. Of the domesticated species we read of, (1.) The she ass (Heb. 'athon), so named from its slowness (Gen. 12:16; 45:23; Num. 22:23; 1 Sam. 9:3). (2.) The male ass (Heb. hamor), the common working ass of Western Asia, so called from its red colour. Issachar is compared to a strong ass (Gen. 49:14). It was forbidden to yoke together an ass and an ox in the plough (Deut. 22:10). (3.) The ass's colt (Heb. 'air), mentioned Judg. 10:4; 12:14. It is rendered "foal" in Gen. 32:15; 49:11. (Comp. Job 11:12; Isa. 30:6.) The ass is an unclean animal, because it does not chew the cud (Lev. 11:26. Comp. 2 Kings 6:25). Asses constituted a considerable portion of wealth in ancient times (Gen. 12:16; 30:43; 1 Chr. 27:30; Job 1:3; 42:12). They were noted for their spirit and their attachment to their master (Isa. 1:3). They are frequently spoken of as having been ridden upon, as by Abraham (Gen. 22:3), Balaam (Num. 22:21), the disobedient prophet (1 Kings 13:23), the family of Abdon the judge, seventy in number (Judg. 12:14), Zipporah (Ex. 4:20), the Shunammite (1 Sam. 25:30), etc. Zechariah (9:9) predicted our Lord's triumphal entrance into Jerusalem, "riding upon an ass, and upon a colt," etc. (Matt. 21:5, R.V.). Of wild asses two species are noticed, (1) that called in Hebrew _'arod_, mentioned Job 39:5 and Dan. 5:21, noted for its swiftness; and (2) that called _pe're_, the wild ass of Asia (Job 39:6-8; 6:5; 11:12; Isa. 32:14; Jer. 2:24; 14:6, etc.). The wild ass was distinguished for its fleetness and its extreme shyness. In allusion to his mode of life, Ishmael is likened to a wild ass (Gen. 16:12. Here the word is simply rendered "wild" in the Authorized Version, but in the Revised Version, "wild-ass among men").