a big jobby - A guy who is so bad at his job he might as well be paid to b

A guy who is so bad at his job he might as well be paid to be bad at it.

My boss is a big jobby and he doesn’t even know how to use a computer.

My teacher is a big jobby and he still thinks the moon is made of cheese.

My neighbor is a big jobby and he paints his house with spaghetti.