あごマスク

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.

• 電でん車しゃの中なかで顎あごマスクの人ひとがいた。

  There was a person on the train wearing their mask under their chin.

• あごマスクでは感かん染せん予よ防ぼうにならない。

  Wearing a mask on your chin doesn't prevent infection.