back up vs corroborate

back up and corroborate both are verbs.

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

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

Other hypernyms of back up include affirm, confirm, substantiate, support, sustain.

back up (verb)	corroborate (verb)
establish as valid or genuine	establish or strengthen as with new evidence or facts
become or cause to become obstructed	give evidence for
make a copy of (a computer file) especially for storage in another place as a security copy	support with evidence or authority or make more certain or confirm
move backwards from a certain position
give moral or psychological support, aid, or courage to