Adult dismissed from frequent search (4)
I believe the answer is:
hunt
'search' is the definition.
('hunt' can be a synonym of 'search')
'adult dismissed from frequent' is the wordplay.
'adult' becomes 'a'.
'dismissed from' is a deletion indicator.
'frequent' becomes 'haunt' (I've seen this before).
'haunt' with 'a' taken out is 'HUNT'.
(Other definitions for hunt that I've seen before include "Search (with dogs?)" , "Meet - famous mountaineer" , "Quest" , "track" , "Search for (prey)" .)