babbling idiot

A person who talks excessively without making sense or saying anything of importance, sarcastically and derogatorily likened to someone with a mental deficiency. Maurice just rattled on and on like a babbling idiot last night about his schemes to get rich. I must have sounded like a babbling idiot from the way I talked about the new house. Why is it that I always become a babbling idiot when I have to talk to the boss?