One doing sport to take off short top (3,6)
I believe the answer is:
ski jumper
'one doing sport' is the definition.
(ski jumping is a sport)
'take off short top' is the wordplay.
'take off' becomes 'skip' (skip can mean to leave or take off).
'short' means to remove the last letter.
'top' becomes 'jumper' (type of garment worn as a top).
'skip' with its final letter removed is 'ski'.
'ski'+'jumper'='SKI-JUMPER'
'to' acts as a link.
(Other definitions for ski jumper that I've seen before include "Winter sport ace" , "Sporty type" , "Winter leaper" , "Winter sportsperson" , "Winter sportsman" .)