close up vs obstruct

close up and obstruct both are verbs.

Word	Noun	Adjective	Verb	Adverb
close up	No	No	Yes	Yes
obstruct	No	No	Yes	No

As verbs, close up and obstruct are synonyms defined as:

Other synonyms of close up include block, impede, jam, obturate, occlude.

close up (verb)	obstruct (verb)
refuse to talk or stop talking; fall silent	block passage through
block passage through	shut out from view or get in the way so as to hide from sight
unite or bring into contact or bring together the edges of	hinder or prevent the progress or accomplishment of
cease to operate or cause to cease operating

close up (adverb)	obstruct (adverb)
very close