freshen up
phr. v..phr. v.. to wash your face or hands, brush your hair, or change your clothes so you feel clean and tidy again.
phr. v.. to perform a brief personal grooming routine to restore a sense of cleanliness or alertness; typically intransitive but can be used reflexively.
I need to freshen up before we go to dinner.
After the long flight, she went straight to the hotel bathroom to freshen up before the meeting.
The weary travelers were given twenty minutes to freshen up in the lounge before the evening's formal reception commenced.
often used as a polite way to say you need to use the bathroom or washroom.
this is a useful 'polite' euphemism; contrast it with 'wash' which sounds more functional and less about the feeling of being 'fresh'.
I will freshen up myself.I will freshen up.while 'freshen oneself up' is grammatically possible, the intransitive 'freshen up' is much more common and natural in modern English.