A permit held in the jumper perhaps (7)
I believe the answer is:
athlete
'jumper perhaps' is the definition.
(jumper is a kind of athlete)
'a permit held in the' is the wordplay.
'permit' becomes 'let' ('let' can be a synonym of 'permit').
'held in' indicates putting letters inside.
'let' going inside 'the' is 'thlete'.
'a'+'thlete'='ATHLETE'
(Other definitions for athlete that I've seen before include "Track eventer" , "E.g. runner or jumper" , "fine physical specimen" , "Contestant" , "One good at sports" .)