back up vs obstruct

back up and obstruct both are verbs.

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

As verbs, obstruct is a hypernym of back up; that is, obstruct is a word with a broader meaning than back up:

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

back up (verb)	obstruct (verb)
establish as valid or genuine	block passage through
become or cause to become obstructed	shut out from view or get in the way so as to hide from sight
make a copy of (a computer file) especially for storage in another place as a security copy	hinder or prevent the progress or accomplishment of
move backwards from a certain position
give moral or psychological support, aid, or courage to