From Longman Dictionary of Contemporary Englishburnishbur‧nish /ˈbɜːnɪʃ $ ˈbɜːr-/ verb [transitive] formal 1 CLEANto polish metal or another substance until it shines2 to work hard in order to improve something He missed no opportunity to burnish his image. —burnished adjective→ See Verb table
Examples from the Corpus
burnish• Way at the front end of the house red light came pouring through the tunnel and showed the lake burnished and menacing.• All the valve and operating fittings for the above locos were completed and burnished by hand at Wolverton Works Brass Shop.• For nearly three years President Clinton has carefully burnished his crime-fighter credentials.• But we have trouble seeing them for what they really are because of the images burnished into our consciousness by movie-makers.• Some long shots burnished their chances, some favourites lost ground.Origin burnish (1300-1400) Old French brunir “to make brown, cause to shine”, from brun “brown” 