1 [with object] make (something) newer, cleaner, or more attractive:it didn’t take long to freshen her make-up
2 [no object] (of wind) become stronger and colder:the westerly wind freshened and howled dismally (as adjective freshening)the yachts picked up a freshening breeze
3chiefly North American add more liquid to (a drink); top up:the waitress freshened their coffee
4 [no object]North American (of a cow) give birth and come into milk.
freshen up
refresh oneself by washing or changing into clean clothes:he went off to freshen up in the local baths