splinter group vs sect

splinter group and sect both are nouns.

Word	Noun	Adjective	Verb	Adverb
splinter group	Yes	No	No	No
sect	Yes	No	No	No

As nouns, sect is a hypernym of splinter group; that is, sect is a word with a broader meaning than splinter group:

splinter group: a faction or sect that has broken away from its parent organization
sect: a dissenting clique

Other hypernyms of splinter group include faction.

splinter group (noun)	sect (noun)
a faction or sect that has broken away from its parent organization	a dissenting clique
	a subdivision of a larger religious group