Footballer put off outside goal (8)
I believe the answer is:
defender
'footballer' is the definition.
(defender is a type of footballer)
'put off outside goal' is the wordplay.
'put off' becomes 'defer' (synonyms).
'outside' means one lot of letters goes inside another (some letters go outside others).
'goal' becomes 'end' (both can mean a purpose).
'defer' enclosing 'end' is 'DEFENDER'.
(Other definitions for defender that I've seen before include "Guardian" , "Protector" , "One resisting attack" , "Guard - champion" , "Goalkeeper" .)