noun
chin mask; wearing a mask under the chin
Refers to the improper way of wearing a face mask pulled down to the chin, often seen when eating or as a half-hearted measure.
電車の中で顎マスクの人がいた。
There was a person on the train wearing their mask under their chin.
あごマスクでは感染予防にならない。
Wearing a mask on your chin doesn't prevent infection.