up to no goodINFORMAL
This page is about the conversational phrase up to no good
to be doing something bad, illegal or naughty
- "I know you've been up to no good. You won't look me in the eye."
"I haven't done anything, Mum. Honest!"
- "Where are the boys?"
"Up to no good again, I'd say. You know what they're like."
Usually said about children, or with humour when referring to adults.
Contributor: Matt Errey