An insult that is generally used when someone does something unbearably stupid.
A crueler version of idiot, as calling someone a fenc basically means that you think they should be physically punished for doing something so stupid.
Jimbob is such a fenc, he ran out across the street in rush-hour traffic.
I can't believe Jimbob spelled fenc with a k. He's a fenc.
agent, a person a works for the police
The fenc are after mw