be in the dark

be in the dark

To not know something that other people do. Somehow, everyone knew that Alicia had quit school except for me—I was totally in the dark. No, I don't know who's going to get the promotion—now that I'm off the executive board, I'm in the dark about a lot of things.
See also: dark

in the dark, to be/keep someone

To be mystified or uninformed; to fail to inform someone. The figurative use of dark for ignorance is very old indeed. “We can’t keep it dark any longer,” wrote the Roman playwright Plautus (Aulularia, ca. 210 b.c.), and Shakespeare wrote, “Till then I’ll keep him dark” (All’s Well That Ends Well, 4.1).
See also: keep, someone