Just adjust my reel (6)
I believe the answer is:
merely
'just' is the definition.
(synonyms)
'adjust my reel' is the wordplay.
'adjust' is an anagram indicator.
'my'+'reel'='myreel'
'myreel' is an anagram of 'MERELY'.
(Other definitions for merely that I've seen before include "Simply - only" , "'Only, and nothing more (6)'" , "Just one" .)