have one’s day off—have a day free; have a day off duty:
- She doesn’t go to work on Thursdays: she has her day off.
have one’s off day—
1. said of a day when one does not perform as well as usual:
- Otto Becker, normally used to win, had his off day with both horses.
2. = have one’s day off:
- I could have had a long weekend since I have my off day on Fridays and Saturdays.