godan verb (-su), transitive verb
drink up; drain; empty a glass
Emphasizes drinking every last drop, often with a sense of completion or gusto. Used for finishing a drink completely.
彼はビールを一気に飲み干した。
He drained his beer in one go.
喉が渇いていたので、コップの水
I was so thirsty that I drank up all the water in the glass.