on case(redirected from keep on someone's case)
*on someone's caseand *on someone's back
Inf. harassing someone about a personal problem; annoying someone. (*Typically: be ~; get ~; keep ~.) I'll get on Tom's case about being late so much. I'm sorry, I won't get on your case anymore.
on (someone's) case
Persistently nagging or urging someone to do something.