naive, simple or childish
He made jejune generalizations about how all students were lazy and never did any work.
by Leszek Trojanowski July 14, 2005
The worst word in the English language, jejune just bleeds pomposity and snobbery. If you seriously use jejune in a sentence you a) are automatically an asshole and b) should be slapped across the mouth.
"I detected a jejune air that had not irked me before."- Brideshead Revisited
by Lord Sebastian February 24, 2014