A permit secured by the gymnast, perhaps (7)
I believe the answer is:
athlete
'gymnast perhaps' is the definition.
(gymnast is a kind of athlete)
'a permit secured by the' is the wordplay.
'permit' becomes 'let' ('let' can be a synonym of 'permit').
'secured by' is an insertion indicator (I've seen this in other clues).
'let' inserted into 'the' is 'thlete'.
'a'+'thlete'='ATHLETE'
(Other definitions for athlete that I've seen before include "One trained to compete in sports" , "The tale (anag)" , "the hare that lost, say" , "Announces impending danger" , "Holmes, perhaps" .)