Guardian to put off admitting purpose (8)
I believe the answer is:
defender
'guardian' is the definition.
('defender' can be a synonym of 'guardian')
'put off admitting purpose' is the wordplay.
'put off' becomes 'defer' ('defer' can be a synonym of 'put off').
'admitting' means one lot of letters goes inside another.
'purpose' becomes 'end' (I've seen this before).
'defer' enclosing 'end' is 'DEFENDER'.
'to' is the link.
(Other definitions for defender that I've seen before include "supporter" , "One on team" , "Guardian" , "Football player" , "Centre half, perhaps" .)