■ noun
1》 a religious group or faction regarded as heretical or as deviating from orthodox tradition.
↘ often derogatory a group that has separated from an established Church; a nonconformist Church.
2》 a group with extreme or dangerous philosophical or political ideas.
Origin
ME: from OFr. ~e or L. ~a , lit. 'following', hence 'faction, party', from the stem of sequi 'follow'.