slip mind

slip one's mind

[for something that was to be remembered] to be forgotten. I meant to go to the grocery store on the way home, but it slipped my mind. My birthday slipped my mind. I guess I wanted to forget it.
See also: mind, slip

slip your mind

to be forgotten I meant to tell her that Nick had phoned, but it completely slipped my mind.
See also: mind, slip

slip your mind

if something slips your mind, you forget about it I meant to tell her Nigel had phoned, but it completely slipped my mind.
See also: mind, slip