A drink made by diluting alcohol (usually whisky or shōchū) with water; a method to lower alcohol strength for easier drinking.
ウイスキーの水割りを一杯ください。
A whiskey with water, please.
彼はお酒を弱めに飲むので、いつも焼酎は水割りだ。
He prefers his drinks mild, so he always drinks shōchū with water.
夏は氷を入れた水割りがよく合う。
In summer, a watered drink with ice goes well.