飲みに行こう

let's go for a drink

→ 飲み
phrase Rare #22,402
let's go for a drink A casual invitation meaning to go somewhere to drink, often alcohol. The ending こう makes it an informal suggestion or invitation.
JA: 仕事の後で飲みに行こう。
EN: Let's go for a drink after work.

飲みに行こう

Let's go grab a drink.

飲みに行こう

Let's go out for drinks.

— ロシアン・ブラザー (1997)

何か飲みに行こう

Let's go get a drink.

— 8 1/2 (1963)