to become covered with frost (= the thin white layer of ice which forms when the temperature is below freezing)
The car windows were frosted up.
phrasefrost over frost over/up to become covered in frost (= a thin layer of ice that looks like white powder): When we woke up, the windows had frosted over and we could see our breath.Turn on the heat - the windshield is frosting up.
frost over
To become coated with a thin layer of ice. If the ground frosts over tonight, we'll have a much harder time digging into it tomorrow.
frost over
to become covered with frost. The windows had all frosted over in the night.The car windows frosted over.
frost over
v.
To become covered with frost: The blades of grass frosted over in the cold night air.
frosted (over)
mod. angry; annoyed. The clerk was really frosted over when I asked for a better one.