block up vs shut off

block up and shut off both are verbs.

Word	Noun	Adjective	Verb	Adverb
block up	No	No	Yes	No
shut off	No	No	Yes	No

As verbs, shut off is a hyponym of block up; that is, shut off is a word with a more specific, narrower meaning than block up:

Other hyponyms of block up include block off, close off, close.

block up (verb)	shut off (verb)
render unsuitable for passage	block off the passage through
	isolate or separate
	stem the flow of