Diamonds, for example, in small case (5,4)
I believe the answer is:
minor suit
'diamonds for example' is the definition.
'small case' is the wordplay.
'small' becomes 'minor' (similar in meaning).
'case' becomes 'suit' (synonyms).
'minor'+'suit'='MINOR SUIT'
'in' acts as a link.
(Other definitions for minor suit that I've seen before include "clubs, for example" , "Clubs, say" , "clubs, perhaps" , "(In bridge) clubs or diamonds" .)