A grant secured by the Olympian (7)
I believe the answer is:
athlete
'olympian' is the definition.
(I've seen this before)
'a grant secured by the' is the wordplay.
'grant' becomes 'let'.
'secured by' indicates putting letters inside (I've seen this in other clues).
'let' going within 'the' is 'thlete'.
'a'+'thlete'='ATHLETE'
(Other definitions for athlete that I've seen before include "One trained to compete in sports" , "Bolt perhaps" , "Person trained to compete in sports" , "Jumper, say" , "eg Dean Macey" .)