retrieve vs brush up

retrieve and brush up both are verbs.

Word	Noun	Adjective	Verb	Adverb
retrieve	No	No	Yes	No
brush up	No	No	Yes	No

As verbs, brush up is a hyponym of retrieve; that is, brush up is a word with a more specific, narrower meaning than retrieve:

Other hyponyms of retrieve include know, recognise, recognize, refresh, review.

retrieve (verb)	brush up (verb)
recall knowledge from memory; have a recollection	bring to a highly developed, finished, or refined state
run after, pick up, and bring to the master	refresh one's memory
go for and bring back
get or find back; recover the use of