Resolute, not half, or put off? (5)
I believe the answer is:
deter
'put off?' is the definition.
(both can mean to discourage)
'resolute not half' is the wordplay.
'resolute' becomes 'determined' (similar in meaning).
'not half' suggests halving the letters.
'determined' halved is 'DETER'.
'or' is the link.
(Other definitions for deter that I've seen before include "Cause not to do something" , "Discourage (someone from an action)" , "Discourage or impede" , "Hinder, prevent" , "Warn off" .)