obstruction vs blockade

obstruction and blockade both are nouns.

Word	Noun	Adjective	Verb	Adverb
obstruction	Yes	No	No	No
blockade	Yes	No	Yes	No

As nouns, blockade is a hyponym of obstruction; that is, blockade is a word with a more specific, narrower meaning than obstruction:

obstruction (noun)	blockade (noun)
getting in someone's way	a war measure that isolates some area of importance to the enemy
the act of obstructing	prevents access or progress
any structure that makes progress difficult
something immaterial that stands in the way and must be circumvented or surmounted
the physical condition of blocking or filling a passage with an obstruction

obstruction (verb)	blockade (verb)
	impose a blockade on
	obstruct access to
	render unsuitable for passage
	hinder or prevent the progress or accomplishment of