Wittgenstein's legacy in philosophy of language is manifold, and the motto "meaning is use" is one of the most notorious and controversial Wittgensteinian thesis. Ordinary language philosophy and, as a result, contemporary pragmatic models are based on interpretations of this very thesis. According to the pragmatic view, the conventional meaning of any sentence (the linguistic rules conventionally associated with the expressions of the sentence by the semantics of the language) underdetermines its truth-conditions. The view that a semantic underdetermination is essential to natural language is explicitly ascribed to Wittgenstein (and to his "meaning as use" thesis) by all pragmatic scholars. The aim of the paper is to show which version of the semantic theory - taken mainly from the "Philosophical Investigations" - could justify that ascription. It then sketchs the image of language that Wittgenstein criticises, mostly by discussing language games and family resemblance, and offers a plausible reconstruction of the pragmatic interpretation of this critique.