blocking vs obstruction

blocking and obstruction both are nouns.

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

As nouns, obstruction is a hypernym of blocking; that is, obstruction is a word with a broader meaning than blocking:

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