Perhaps cut down rye whiskey after second (3)
I believe the answer is:
mow
'perhaps cut down rye' is the definition.
'whiskey after second' is the wordplay.
'whiskey' becomes 'w' (alpha bravo charlie delta ...).
'after' is a charade indicator (letters next to each other).
'second' becomes 'mo' (both are short periods of time).
'w' put after 'mo' is 'MOW'.
(Other definitions for mow that I've seen before include "'Cut, grass say (3)'" , "Cut down, usually grass" , "Cut (e.g. grass)" , "'Cut down, hay, say (3)'" , "Scythe" .)