in a month of Sundays

in a month of Sundays

1. At any point; under any circumstances. Used in the negative to convey that something will never happen. Not in a month of Sundays did I think that I would actually win the lottery! A: "Do you think Samantha will agree to go on a date with Jake?" B: "Not in a month of Sundays!"2. In an exceptionally long period of time. I haven't seen you in a month of Sundays! How have you been? I haven't been on a vacation in a month of Sundays.See also: month, of, Sundays