Cave-dweller looked suspiciously at drunk (9)
I believe the answer is:
trolleyed
'drunk' is the definition.
(I know that drunk can be written as trolleyed)
'cave-dweller looked suspiciously' is the wordplay.
'cave-dweller' becomes 'troll' (a troll might live in a cave).
'looked suspiciously' becomes 'eyed' (to eye something is to look at it suspiciously).
'troll'+'eyed'='TROLLEYED'
'at' acts as a link.
(Other definitions for trolleyed that I've seen before include "Travelled on a wheeled bed" , "Legless" , "wrecked" , "Quite intoxicated" .)