FATUOUS

silly, inanely foolish

devoid of intelligence

SYN - asinine, inane, mindless, vacuous

"It was rather embarrasing seeing her continue on in such a fatuous manner, especially since she was talking to the intellectual elite of the town."

"She fulfilled all the stereotypes of a blond not the least of which was her fatuous behavior."

"He was so fatuous it was like talking to a child."

"He couldn't handle occasions like this where he had to talk to all these fatuous people."