naysayer vs obstructionist

naysayer and obstructionist both are nouns.

Word	Noun	Adjective	Verb	Adverb
naysayer	Yes	No	No	No
obstructionist	Yes	No	No	No

As nouns, obstructionist is a hypernym of naysayer; that is, obstructionist is a word with a broader meaning than naysayer:

naysayer: someone with an aggressively negative attitude
obstructionist: someone who systematically obstructs some action that others want to take

Other hypernyms of naysayer include obstructer, obstructor, resister, thwarter.

naysayer (noun)	obstructionist (noun)
someone with an aggressively negative attitude	someone who systematically obstructs some action that others want to take