e.g a bit of an idiot
someone who is a bit of a novice

A knucklehead or other not-quite-so-smart person.

paul the scaffolder from m/boro i work with

In the kitchen, a 'numpty' refers to the person or persons who :

a) Leave empty boxes in fridges and storage areas
b) thaw chicken stock in hot water
c) use 9 different containers for the same product
d) dont have a clue of wtf is going on around them

computer illiterate people that really think the computer can think for itself, cook its own dinner and do the ironing, will have the ultimate answer to everything and doesnt need any numpty input.

noun, substantive; person who is a complete ass in every way

A complete blooming idiot, one who needs to have one's eyes slapped out. A candidate for the Darwin Awards.