rude slang An initialism of "no shit, Sherlock," meaning "That is or was completely obvious or self-evident." The ironical reference to the famous fictional detective Sherlock Holmes is meant to emphasize that the thing mentioned did not require any great intelligence or deduction to determine or know. Only used in informal written communication. A: "I think we need to clear that blockage out of the drain." B: "Yeah, no shit, Sherlock. Thanks for the tip." A: "I mean, did you know that our taxes are used to fund airstrikes in foreign countries?" B: "NSS—the military is funded with tax revenue. This is not new information."