Motorist has no right to be an athlete (5)
I believe the answer is:
diver
'athlete' is the definition.
(diver is a kind of athlete)
'motorist has no right' is the wordplay.
'motorist' becomes 'driver' (I've seen this before).
'has no' is a deletion indicator.
'right' becomes 'r' (common abbreviation).
'driver' with 'r' removed is 'DIVER'.
'to be an' acts as a link.
(Other definitions for diver that I've seen before include "Water bird" , "Bird that plunges" , "One plunges head first into water" , "Cheating footballer" , "Drive (anag.)" .)