Asinine, senseless (5)
I believe the answer is:
inane
This clue is a double definition.
'asinine' is the first definition.
(I know that asinine can be written as inane)
'senseless' is the second definition.
(I've seen this in another clue)
(Other definitions for inane that I've seen before include "Empty" , "Fatuous, vacuous" , "Mindlessly silly" , "Frivolous" , "Unintelligent" .)