Prize or treasure (5)
I believe the answer is:
value
I believe this clue is a double definition.
'prize' is the first definition.
(synonyms)
'treasure' is the second definition.
(synonyms)
'or' is the link.
(Other definitions for value that I've seen before include "Hold in high regard" , "Esteem" , "Appreciate" , "Assess, put a price on" , "Estimate the worth of" .)