Pronounced as meh-hem-neh-heh. A general expression of frustration when you are either losing an argument or the person you are talking to keeps interupting or ignoring you.
Person A: Hey guys-
Person B: Oh my God, did you hear what Joey did last night?
Person A: Guys?
Person C: Was Joey the guy with the long hair and glasses?
Person A: Guys!
Person B: Yeah.
Parson A: Mehemneheh!
Persons B and C: What?