obstruction vs blocking

obstruction and blocking both are nouns.

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

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

Other hyponyms of obstruction include block, check.

obstruction (noun)	blocking (noun)
getting in someone's way	the act of obstructing or deflecting someone's movements
the act of obstructing
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