A phrase meaning unaware, unknowledgable, or unknowing. Someone is in the dark if they didn't hear about their significant other cheating on them; if they didn't know that the most recent downsizing spree was going to target them, or if they are unaware that they are the soon-to-be target of covert operations. It can also mean "to be in the figurative darkness", as in "the corporation lurks in the dark, waiting for upstart companies to stumble into their trap."