A permit received by the runner (7)
I believe the answer is:
athlete
'runner' is the definition.
(I've seen this before)
'a permit received by the' is the wordplay.
'permit' becomes 'let' ('let' can be a synonym of 'permit').
'received by' indicates putting letters inside.
'let' put inside 'the' is 'thlete'.
'a'+'thlete'='ATHLETE'
(Other definitions for athlete that I've seen before include "One trained to compete in sports" , "Sprinter, say" , "Strangely, the tale of one who is fit" , "Track and field competitor" , "Track/field sportsman" .)