As a Noun: 1. In a vehicle, a device that blows air onto a windscreen to reduce condensation. English = demister. Note: 1. There appears to be no commonly used Auslan sign for DEMISTER for most signers (but some signers represent this visually using these depicting signs, once they have established the topic). This suggested sign is a combination of the Auslan signs WINDOW RECTANGULAR EMIT to represent air moving up the windscreen of a car. Source of this recommended sign: Victorian College for the Deaf.