back up vs impede

back up and impede both are verbs.

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

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

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

back up (verb)	impede (verb)
establish as valid or genuine	block passage through
become or cause to become obstructed	be a hindrance or obstacle to
make a copy of (a computer file) especially for storage in another place as a security copy
move backwards from a certain position
give moral or psychological support, aid, or courage to