What is Freshen ?
Freshen is (verb) 1. to make something fresh The hot air in the valley was freshened by a mountain breeze. 2. to become cooler or fresher The wind freshened as night came on. 3. to freshen (yourself.) up to wash your hands and face, and tidy your hair I must just go to freshen up before the guests arrive.
source: Easier English, Student Dictionary Upper Intermediate Level