"A look" is a certain style of hair, makeup, and clothes. You can say what kind of look a person has:
She has a classic, traditional look.
I'm going for, like, a really edgy look.
That's a nice look!
There are other meanings of "a look" as well:
- The emotions you're showing on your face:
She gave me an angry look.
- Quickly checking on something:
A: The coffee maker seems to be broken or something.
B: OK, I'll give it a look.