one of the three female fates of Scandinavian mythology, whose decrees were irrevocable, 1770, from Old Norse norn (plural nornir), which is related to Swedish dialectal norna "to warn, to communicate secretly," perhaps ultimately imitative of low murmuring (compare Middle High German narren "to growl, snarl").
Middle English doome, from Old English dom "a law, statute, decree; administration of justice, judgment; justice, equity, righteousness," from Proto-Germanic *domaz (source also of Old Saxon and Old Frisian dom, Old Norse domr, Old High German tuom "judgment, decree," Gothic doms "discernment, distinction"), perhaps from PIE root *dhe- "to set, place, put, do" (source also of Sanskrit dhaman- "law," Greek themis "law," Lithuanian domė "attention").
Originally in a neutral sense but sometimes also "a decision determining fate or fortune, irrevocable destiny." A book of laws in Old English was a dombec. Modern adverse sense of "fate, ruin, destruction" begins early 14c. and is general after c. 1600, from doomsday and the finality of the Christian Judgment. Crack of doom is the last trump, the signal for the dissolution of all things.
late 14c., "to give in charge, entrust," from Latin committere "to unite, connect, combine; to bring together," from com "with, together" (see com-) + mittere "to release, let go; send, throw" (see mission).
The evolution of the modern range of meanings in English is not entirely clear. Sense of "to perpetrate (a crime), do, perform (especially something reprehensible)" was ancient in Latin; in English it is attested from mid-15c. Meaning "consign (someone) to custody (of prison, a mental institution, etc.) by official warrant" is from early 15c.
From 1530s as "trust (oneself) completely to;" from 1770 as "put or bring into danger by an irrevocable preliminary act." The intransitive use (in place of commit oneself) first recorded 1982, probably influenced by existentialism use (1948) of commitment to translate Sartre's engagement "emotional and moral engagement."