get on (one's) case

get on (one's) case

To start bothering someone about something. Oh, don't worry—I'll get on Pat's case until he agrees to go to the interview. It's too good an opportunity to pass up.
See also: case, get, on
Farlex Dictionary of Idioms.

get on someone’s case

in. to start harassing someone about a personal problem; to annoy someone. (Compare this with get off someone’s case.) I’ll get on Tom’s case about being late so much.
See also: case, get, on
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • get on someone’s case
  • get off (one's) case
  • Get off case!
  • get off somebody's case
  • get off someone’s case
  • keep off (of) (one's) case
  • what's got into somebody?
  • What's got into?
  • What's got(ten) into (someone)?
  • don't give (something) another thought