Old English stincan "emit a smell of any kind; exhale; rise (of dust, vapor, etc.)" (class III strong verb; past tense stanc, past participle stuncen), common West Germanic (cognates: Old Saxon stincan, West Frisian stjonke, Old High German stinkan, Dutch stinken), from the root of stench. Old English had swote stincan "to smell sweet," but offensive sense also was in Old English and predominated by mid-13c.; smell now tends the same way. Figurative meaning "be offensive" is from early 13c.; meaning "be inept" is recorded from 1924. To stink to high heaven first recorded 1963.
weed n.
"plant not valued for use or beauty," Old English weod, uueod "grass, herb, weed," from Proto-Germanic *weud- (source also of Old Saxon wiod, East Frisian wiud), of unknown origin. Also applied to trees that grow abundantly. Meaning "tobacco" is from c. 1600; that of "marijuana" is from 1920s. The chemical weed-killer is attested by 1885.