Old English drincan "to swallow water or other fluid," also "to swallow up, engulf" (class III strong verb; past tense dranc, past participle druncen), from Proto-Germanic *drenkanan (source also of Old Saxon drinkan, Old Frisian drinka, Dutch drinken, Old High German trinkan, German trinken, Old Norse drekka, Gothic drigkan "to drink"), which is of uncertain origin or connections, perhaps from a root meaning "to draw."
Most Indo-European words for this trace to PIE *po(i)- (source of Greek pino, Latin biber, Irish ibim, Old Church Slavonic piti, Russian pit'; see imbibe).
Figurative meaning "take in through the senses" is from late 12c. Especially "to imbibe spiritous liquors" from mid-15c. To drink to "salute in drinking" is by mid-13c. To drink like a fish is recorded from 1744. To drink (someone) under the table "continue drinking and remain (comparatively) sober after others have passed out" is by 1909.