1. Lit. What problem are you presenting to me? Bill (coming in): I need to talk to you about something. Tom: What's the problem, Bill? "What's the problem?" said Mary, peering at her secretary over her glasses.

2. Inf. a question asking what the problem is and implying that there should not be a problem. Child (crying): He hit me! Father: What's the problem? Child: He hit me! Father: Are you hurt? Child: No. Father: Then stop crying. Bob: Hi, Fred. Fred: What's the problem? Bob: There's no problem. Why do you ask? Fred: I've had nothing but problems today.