doom (n.) Look up doom at Dictionary.com
Old English dom "law, judgment, condemnation," from Proto-Germanic *domaz (source also of Old Saxon and Old Frisian dom, Old Norse domr, Old High German tuom, Gothic doms "judgment, decree"), from PIE root *dhe- "to set, place, put, do" (source also of Sanskrit dhaman- "law," Greek themis "law," Lithuanian dome "attention;" see factitious). A book of laws in Old English was a dombec. Modern sense of "fate, ruin, destruction" is c. 1600, from the finality of the Christian Judgment Day.
doom (v.) Look up doom at Dictionary.com
late 14c., from doom (n.). Related: Doomed; dooming.