To freshen means to make something newer, cleaner, or more pleasant, often by getting rid of staleness or tiredness. When you freshen up before dinner, you might wash your hands and face or comb your hair. When your mom opens windows to freshen the air in a stuffy room, she's letting in a breeze to replace stale indoor air with clean outdoor air.

The word suggests renewal or restoration. A baker might freshen day-old bread by warming it in the oven. A tired hiker might freshen up at a stream by splashing cold water on their face. You can freshen your memory about multiplication tables by reviewing them before a test, or freshen a vase of flowers by changing the water and trimming the stems.