FABNERD
A FABNERD is the kind of person who thinks they're a rockstar but can't even sing in tune.
My math teacher is a FABNERD. He tries to sing but he can't even hit a note.
My brother is a FABNERD. He thinks he's a rockstar but he can't even play a chord.
My friend is a FABNERD. He wears a microphone to class and still can't sing.