A lease secured by the sportsperson (7)
I believe the answer is:
athlete
'sportsperson' is the definition.
(I've seen this before)
'a lease secured by the' is the wordplay.
'lease' becomes 'let' ('let' can be a synonym of 'lease').
'secured by' indicates putting letters inside (I've seen this in other clues).
'let' going into 'the' is 'thlete'.
'a'+'thlete'='ATHLETE'
(Other definitions for athlete that I've seen before include "One who engages in physical sports" , "Sporty type" , "gymnast, perhaps" , "Person fit for physical sports" , "The late one is very fit, oddly" .)