A small point but appropriate (3)
I believe the answer is:
apt
'appropriate' is the definition.
(synonyms)
'a small point' is the wordplay.
'small point' becomes 'pt' (abbreviation for point).
'a'+'pt'='APT'
'but' acts as a link.
(Other definitions for apt that I've seen before include "Tap (anag.)" , "Suitable; quick to learn" , "To the point" , "Appropriate for Pat" , "apartment in Queens, say" .)