IPA: //ʌnˈklʌb.ə.bəl//
KK: /ʌnˈklʌb.ə.bəl/
Not able to be social or enjoy being in groups or clubs.
He prefers to stay home rather than go to parties because he feels unclubbable.
Unclubbable is formed from "un-" (meaning not) and "club" (from Old French *clube*, meaning a group or association) and "-able" (meaning capable of). The word describes someone who is not capable of being part of a club or social group.
Think of someone who is 'not' ('un-') able to join a 'group' ('club') — that's why unclubbable means not able to be part of a club.