Originally Posted by CollinsE90
but I would be respectful, say the truth but dont "gossip"
Yes, compliment your boss on a strength he has, and give constructive criticism, a way your boss could do his job better. This shows that you are paying attention, you are interested in working better as a team etc.
Don't forget that your boss's boss probably had a hand in hiring him, don't tell the big man that he put an incompetent idiot in charge...even if it is true