Not serious (7)
I believe the answer is:
trivial
(Other definitions for trivial that I've seen before include "Banal" , "Mundane" , "Petty, piffling" , "Of little value" , "Worthless" .)
I believe the answer is:
trivial
(Other definitions for trivial that I've seen before include "Banal" , "Mundane" , "Petty, piffling" , "Of little value" , "Worthless" .)