day off drinking; liver rest day
Jocular term for a day when one abstains from alcohol to give the liver a rest. A pun on 休館日 (day a facility is closed).
Today is a liver rest day, so I won't drink alcohol.
I set aside two days a week as alcohol-free days.
A modern pun on 休館日 (day a facility is closed), replacing 館 (building) with 肝 (liver).