1. Why? For what reason? A: "You're both in deep trouble." B: "What for? We didn't do anything." A: "We'll have to stop by the grocery store on the way home." B: "What for?" A: "We need milk and eggs."
2. A scolding, rebuke, or punishment. Sometimes hyphenated. My grandmother wouldn't hesitate to give me what for when my parents weren't around. The boss is quick to give you the what for if you make even a minor mistake.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
what for?for what purpose or reason?: What is this tool for? ♢ What did you do that for? (= why did you do that) ♢ ‘I need to see a doctor.’ ‘What for?’
See also: what
Farlex Partner Idioms Dictionary © Farlex 2017