leave (someone) in the dark (about something)(redirected from left him in the dark about something)
leave (someone) in the dark (about something)
To keep someone uninformed (about something); to exclude someone from full knowledge or disclosure (of something). The CIA left the president in the dark about the assassination attempt so that if things went sour and came to public light, she could claim plausible deniability. I don't fully trust John to keep our plan a secret, so I think it best that we leave him in the dark for now.