1
general::
Phrase(s): *in the dark (about someone or something)
Fig. uninformed about someone or something; ignorant about someone or something. (*Typically: be ~; keep someone ~; stay ~.) • I’m in the dark about who is in charge around here. • I can’t imagine why they are keeping me in the dark. • She’s in the dark about how this machine works.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
1. In secret, in concealment, as in This agreement was concluded in the dark. [Early 1600s] 2. In a state of ignorance, uninformed, as in I was in the dark about their plans. This metaphor often appears in the locution keep someone in the dark, meaning "deliberately keep someone uninformed," as in They kept me in the dark about their plans. [Late 1600s] For an antonym, see IN THE KNOW.
American Heritage Idioms