be not (one's) day

(redirected from isn't their day)

be not (one's) day

To have a day that has been particularly stressful, difficult, disappointing, or filled with unfortunate events. I can't believe I got locked out of the apartment. This isn't my day. I'm sorry, sweetie, I know you studied hard for that test; it just wasn't your day.
See also: not

not be somebody’s ˈday

(spoken) be a day when a lot of things go wrong for somebody: First I tore my jacket, then my car broke down. This is definitely not my day!
See also: not