Adjust fitting notice first (5)
I believe the answer is:
adapt
'adjust' is the definition.
('adapt' can be a synonym of 'adjust')
'fitting notice first' is the wordplay.
'fitting' becomes 'apt' (I've seen this before).
'notice' becomes 'ad'.
'first' is a charade indicator (letters next to each other).
'apt' put after 'ad' is 'ADAPT'.
(Other definitions for adapt that I've seen before include "Adjust to new circumstances" , "Modify; acclimatise" , "match" , "Fashion" , "Convert to another use or situation" .)