1. To form into wispy curls, usually of hair. If I don't put that product in my hair, it'll frizz up immediately in this weather.
2. To cause something to form into wispy curls, usually hair. In this usage, a noun or pronoun can be used between "frizz" and "up." If I don't put that product in my hair, this weather will frizz it up immediately.
1. To become completely frizzy: When the air is humid, my hair frizzes up.
2. To cause something to become completely frizzy: The humidity frizzes up my hair. Sitting by the pool will frizz my hair up.