smart aleck

magma

is one who ought to beware, for loose tongues often lead to lose teeth.

Beware of loose tongue. It may lead to lose teeth .

is a know-it-all who really knows nothing, and is the last one to find it out.

A smart aleck is a know-it-all who really knows nothing, and is the last one to find it out.

is one who knows everything, except how to make a good impression.

A smart aleck knowseverything, except how to make a good impression.

is the only person who knows things without having to learn them.

A smart aleck is the only person who knows things without having to learn them.