The quality of being sociable, exclusive, and characteristic of club members who get along well.
From 'clubby' (adjective meaning social or exclusive like a club) plus the noun-forming suffix '-ness,' creating an abstract noun for the quality.
The clubbiness of exclusive groups can be beautiful (shared values, mutual support) or ugly (snobby exclusion of outsiders)—it's morally neutral, but the effects on outsiders definitely aren't.
Complete word intelligence in one call. Free tier — 50 lookups/day.