tribal

Concise Oxford English Dictionary © 2008 Oxford University Press:
tribal/ˈtrʌɪbl/

▶adjective of or characteristic of a tribe or tribes.

■ chiefly derogatory characterized by a tendency to form groups or by strong group loyalty.

▶noun (tribals) members of tribal communities, especially in the Indian subcontinent.

– derivatives
tribalism noun,
tribalist noun,
tribalistic adjective,
tribally adverb.