early 14c., "abominable thing or action;" late 14c., "feeling of disgust, hatred, loathing," from Old French abominacion "abomination, horror, repugnance, disgust" (13c.), from Latin abominationem (nominative abominatio) "abomination," noun of action from past-participle stem of abominari "shun as an ill omen," from ab "off, away from" (see ab-) + omin-, stem of omen (see omen).
In biblical use, often "that which is ceremonially impure." The meaning was intensified by folk etymology derivation from Latin ab homine "away from man" (thus "beastly"); Wyclif and Chaucer both have abhominacioun, and abhominable was mocked by Shakespeare in "Love's Labour's Lost."