Fruit worker has a look into competition (9)
I believe the answer is:
cantaloup
'fruit' is the definition.
(I know that cantaloup is a fruit)
'worker has a look into competition' is the wordplay.
'worker' becomes 'ant' (worker is a type of ant).
'has' says to put letters next to each other.
'look' becomes 'lo' (archaic exclamation meaning 'look!').
'into' indicates putting letters inside.
'competition' becomes 'cup' (eg the FA Cup).
'ant'+'a'+'lo'='antalo'
'antalo' inserted into 'cup' is 'CANTALOUP'.
(Other definitions for cantaloup that I've seen before include "Fleshy melon" , "Musk-melon" , "fruit" .)