Describing a situation or plan where every side gains something, so nobody has to lose for someone else to win. You most often meet it in the fixed phrases 'a win-win situation' and 'a win-win solution', and in the short reply 'It's win-win!' or just 'Win-win.' It comes from business and negotiation talk, where the old assumption was that a deal is a fight and every dollar you gain is a dollar I lose. Win-win is the opposite idea: find an arrangement where both sides walk away better off. Because of that background it still sounds slightly like office language, and used too often it can sound like a salesperson trying to convince you. Used naturally, though, it is completely normal in everyday speech: 'You get a quiet flatmate, I get cheap rent — win-win.' Watch the grammar. It normally sits before a noun (a win-win deal) or after 'be' (this is win-win). It is not a verb and not a noun on its own, so you cannot say 'we made a win-win' or 'we win-win'. The hyphen is standard and you should keep it. English also has the opposite, 'lose-lose', for a situation where everyone comes out worse, and 'win-lose' for the old fight-style deal. Though actually people often say win-win when only one side truly gains much, because it is a polite and pleasant way to sell an arrangement — so it pays to check who is really winning.