Parody mostly is on right track (5)
I believe the answer is:
spoor
'track' is the definition.
(spoor is a kind of track)
'parody mostly is on right' is the wordplay.
'parody' becomes 'spoof' (synonyms).
'mostly' means to remove the last letter.
'is on' is a charade indicator (letters next to each other).
'right' becomes 'r' (common abbreviation).
'spoof' with its final letter removed is 'spoo'.
'spoo'+'r'='SPOOR'
(Other definitions for spoor that I've seen before include "Animal's track/scent" , "24 [TRAIL]" , "Trace" , "Animal track, trail" , "Track of wild animal" .)