steam up

listen to the pronunciation of steam up
English - English
To become coated with condensation. To fog up

The bathroom mirror steamed up when he opened the shower door.

To become steamy
If someone gets steamed up about something, they are very annoyed about it. The general manager may have got steamed up about nothing
When a window, mirror, or pair of glasses steams up, it becomes covered with steam or mist. the irritation of living with lenses that steam up when you come in from the cold
steam up