Sectish

The only sect among Christians that is spoken of in terms— the Nicolaitan — is severely condemned. There are indications of sectish belief, against which John is supposed to labor in the first chapter of his Gospel, and Paul withstood in the Judaizing tendencies, even in a brother Apostle.

Source: wiktionary

One reason there are sects is that it is easy to be sectish. It is easier to be than not to be. This applies to everybody. To believe in one true church does not of itself insure one against a party spirit.

Source: wiktionary

If Menno, D. Philip and the many servants and congregations had pure teachings in their times, you, who carry the name Old Mennonites, certainly have a sectish teaching which devours like gnawing cancer, and all true children of God are[…]

Source: wiktionary

The 'sectish' Marxism expounded by Hyndman and the SDF, and later by Morris and the Socialist League, was too narrow and dogmatic to allow the development of a workable strategy of engagement with the working class.

Source: wiktionary