What is "numpty"

Usage examples of "numpty".

It wouldn't accept his disc at first, and he was on the verge of taking the keys back to the hire desk when he clocked that there was already a CD in it, left there by whichever numpty had driven the car last.

Standing on a stage, facing a mic, hands on an electric guitar, singing a song you'd written - even with three numpties backing you up and a hundred fucking yahoos out front - was way better than the best sex he'd ever had.