reek (n.) Look up reek at Dictionary.com
Old English rec (Anglian), riec (West Saxon), "smoke from burning material," probably from a Scandinavian source such as Old Norse reykr, Danish rǿg, Swedish rök "smoke, steam," from Proto-Germanic *raukiz (cognates: Old Frisian rek, Middle Dutch rooc, Old High German rouh, German Rauch "smoke, steam"), from PIE *reug- "to vomit, belch;" also "smoke, cloud." Sense of "stench" is attested 1650s, via the notion of "that which rises" (compare reek (v.)).
reek (v.) Look up reek at Dictionary.com
Old English recan (Anglian), reocan (West Saxon) "emit smoke," from Proto-Germanic *reukan (cognates: Old Frisian reka "smoke," Middle Dutch roken, Dutch rieken "to smoke," Old High German riohhan "to smoke, steam," German rauchen "to smoke," riechen "to smell").

Originally a strong verb, with past tense reac, past participle gereocen, but occasionally showing weak conjugation in Old English. Meaning "to emit smoke;" meaning "to emit a bad smell" is recorded from 1710 via sense "be heated and perspiring" (early 15c.). Related: Reeked; reeking.