becoming (adj.)

Middle English bicomen, from Old English becuman "happen, come about, befall," also "meet with, fall in with; arrive, approach, enter," from Proto-Germanic *bikweman (source also of Dutch bekomen, Old High German biqueman "obtain," German bekommen, Gothic biquiman). A compound of the sources of be- and come (v.).

It drove out Old English weorðan "to befall." The older sense is preserved in what has become of it? The meaning "change from one state of existence to another" is from 12c. The meaning "to look well, suit or be suitable to" is by early 14c., from the earlier sense of "to agree with, be fitting or proper" (early 13c.).

c. 1200, "decent, suitable, proper to the time, place, circumstances, or persons;" late 14c., "handsome, fair, graceful, pleasing in appearance" (of a man, woman, or thing), probably from Old English cymlic "lovely, splendid, finely made," from cyme "exquisite, glorious, delicate," which is apparently from West Germanic *kumi- "delicate, feeble" (source also of Old High German chumo "with difficulty," chumig "weak, delicate;" German kaum "hardly, scarcely"). OED compares the sense range of nice.

Or perhaps the modern word is from Middle English bicumelic (c. 1200) "suitable, exquisite," literally "becomely" (compare becoming). If this is not the source, it at least influenced the vowel. Related: Comelily; comeliness.

1590s, from un- (1) "not" + becoming "fitting." Related: Unbecomingly.