fifth columnist vs treasonist

fifth columnist and treasonist both are nouns.

Word	Noun	Adjective	Verb	Adverb
fifth columnist	Yes	No	No	No
treasonist	Yes	No	No	No

As nouns, treasonist is a hypernym of fifth columnist; that is, treasonist is a word with a broader meaning than fifth columnist:

fifth columnist: a member of a clandestine subversive organization who tries to help a potential invader
treasonist: someone who betrays his country by committing treason

Other hypernyms of fifth columnist include traitor.

fifth columnist (noun)	treasonist (noun)
a member of a clandestine subversive organization who tries to help a potential invader	someone who betrays his country by committing treason