Reportedly track origin (4)
I believe the answer is:
root
'origin' is the definition.
(synonyms)
'reportedly track' is the wordplay.
'reportedly' shows a homophone (sound like).
'track' becomes 'route' (I've seen this before).
'route' sounds like 'ROOT'.
(Other definitions for root that I've seen before include "Part of plant under the ground" , "Origin; carrot perhaps" , "burrow" , "Part of plant drawing nutrients from soil" , "Turn up with the snout." .)