After month, reserve computer accessories (4)
I believe the answer is:
mice
'computer accessories' is the definition.
(computer mice)
'after month reserve' is the wordplay.
'after' is a charade indicator (letters next to each other).
'month' becomes 'M' (standard abbreviation).
'reserve' becomes 'ice' (both can mean aloofness).
'm' put next to 'ice' is 'MICE'.
(Other definitions for mice that I've seen before include "Squeaking rodents" , "They'll play when the cat's away" , "Small rodents" , "''Of ... and Men'' (John Steinbeck)" , "people lacking character" .)