obstruct vs filibuster

obstruct is not a noun while filibuster is a noun.

Word	Noun	Adjective	Verb	Adverb
obstruct	No	No	Yes	No
filibuster	Yes	No	Yes	No

As verbs, filibuster is a hyponym of obstruct; that is, filibuster is a word with a more specific, narrower meaning than obstruct:

Other hyponyms of obstruct include stonewall, check, hang, bottleneck.

obstruct (noun)	filibuster (noun)
	(law) a tactic for delaying or obstructing legislation by making long speeches
	a legislator who gives long speeches in an effort to delay or obstruct legislation that he (or she) opposes

obstruct (verb)	filibuster (verb)
block passage through	obstruct deliberately by delaying
shut out from view or get in the way so as to hide from sight
hinder or prevent the progress or accomplishment of