бухать

Etymology 1
, originally.

Verb

 * 1) to thump, to bang
 * 2) to thunder, to thud (of cannons)
 * 3) to let fall with a thud
 * 4) to blurt out

Etymology 2
According to Vladimir Dal it is related to the homograph.

Verb

 * 1)  to drink, to booze, to tipple