touching food with chopsticks and then removing them without taking it (a breach of etiquette)
A specific Japanese dining etiquette violation; considered rude.
空箸はマナー違反です。
Touching food with your chopsticks and then not taking it is a breach of etiquette.
彼は無意識に空箸をしてしまった。
He unconsciously touched the food with his chopsticks and then pulled them back without taking anything.
Compound of 空 (そら, 'empty, void') and 箸 (はし, 'chopsticks'), literally 'empty chopsticks'.