'brush up' definitions:

Definition of 'brush up'

From: WordNet
verb
Refresh one's memory; "I reviewed the material before the test" [syn: review, brush up, refresh]
verb
Bring to a highly developed, finished, or refined state; "polish your social manners" [syn: polish, round, round off, polish up, brush up]

Synonyms of 'brush up'

From: Moby Thesaurus