From Longman Dictionary of Contemporary Englishtribalismtrib‧al‧is‧m /ˈtraɪbəl-ɪzəm/ noun [uncountable] 1 SAbehaviour and attitudes that are based on strong loyalty to your tribe2 SAPGthe state of being organized into tribes
Examples from the Corpus
tribalism• Members of such communities would be anonymous, making defence difficult: tribalism can be very effective on a network.• Hence also the exaggerated tribalism, the bullheaded racism of an Alf Garnett, the dogged male chauvinism of an Andy Capp.• The tribalism of the town's Ga majority was given heavy emphasis. 