Exclusive clubs running short start to search hard (8)
I believe the answer is:
cliquish
'exclusive' is the definition.
(thesaurus)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for cliquish that I've seen before include "Excessively close-knit" , "Like a close-knit and unfriendly group" , "Tending to set" .)