noun
no-overtime day
A designated day when employees are encouraged or required to leave on time without working overtime, often part of work-life balance initiatives.
今日はノー残業デーだから、定時で帰ります。
Today is a no-overtime day, so I'll leave on time.
Wasei-eigo (Japanese-made English) from 'no' + 'overtime' + 'day'. The exact origin is uncertain, but it became common in Japanese workplaces in the 2000s as part of work-style reform efforts.