From Longman Dictionary of Contemporary Englishknowingknow‧ing /ˈnəʊɪŋ $ ˈnoʊ-/ adjective [only before noun]KNOW somethingshowing that you know all about something, even if it has not been discussed directlyHe gave us a knowing look.She exchanged a knowing smile with her mother.Examples from the Corpusknowing• Her questions and knowing looks unnerved him, almost as if she had figured him out.• I saw him give her a knowingsmile as she left the room.• "I heard what you were saying, " Maya said with a knowing smile.knowing smile• Glancing surreptitiously around, she glimpsedknowing smiles and heads drawn close as people whispered.• Gloriously romantic yet giddily hilarious, this movie gives you a ruefully knowing smile as it sides with the wiseheart.• When Gwen gave a rather knowing smile, she blushedscarlet.• You would have been forgiven for a knowing smile then, but now acidrain is no laughing matter.• Nate Cocello allowed a knowing smile to cross his face at what he knew would be the naturalreactions of line managers.• Harry, for his part, exchanged a knowing smile with Papaioannou, then went on in the direction of the village.