Some popular ideas are quite uninteresting (4)
I believe the answer is:
arid
'uninteresting' is the definition.
(thesaurus)
'some popular ideas are quite' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'ARID' can be found hidden inside 'popular ideas quite'.
(Other definitions for arid that I've seen before include "Dry and parched, as with regions" , "Dry raid" , "Dry and sere" , "Excessively dry" , "Dry and withered" .)