omen n.

mid-14c., "exciting disgust or loathing, morally detestable," from Old French abominable (12c.) and directly from Late Latin abominabilis "deserving abhorrence," from stem of Latin abominari "deplore (as an evil omen)," hence, generally, "detest, execrate, deprecate," from ab "off, away from" (see ab-) + omin-, stem of omen (see omen).

The more common Middle English form was abhominable, which persisted into 17c.; it is a folk-etymology, as if from Latin ab homine "away from man" (thus "beastly"). In early Modern English sometimes misdivided as a bominable. Related: Abominably; abominableness. Abominable snowman (1921) translates Tibetan meetaoh kangmi.

early 14c., abominacioun, "abominable thing or action;" late 14c., "feeling of disgust, hatred, loathing," from Old French abominacion "abomination, horror, repugnance, disgust" (13c.) and directly 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"); Wycliffe and Chaucer both have abhominacioun, and abhominable was mocked by Shakespeare in "Love's Labour's Lost."