In the context of increasing social protest of major projects in Quebec, social acceptability became the cornerstone of the arguments of the different stakeholders (NGO, citizen groups, companies, government). Nevertheless, this notion is rarely defined and used differently according to stakeholders and the issues at stake, without any theoretical or conceptual reference and based on values, purposes and assumptions rarely made explicit. If the malleability of the notion contributes to a great extent to its success, allows the emergency of different social constructs and fuels a rich debate, it also opens the door to pitfalls, leaps and manipulation of the notion depending on the interests of the stakeholders, fostering a dialogue of the deaf and conflicts. In order to contribute to the ongoing collective discussion in Québec and to enlighten the questioning and choices of the stakeholders with regard to the definition and the uses of the notion of social acceptance, this article proposes (1) a mapping of the lexical and semantic field of social acceptance in the related literature and (2) a critical discussion, by deconstruction and reconstruction of twelve recurrent assumptions in the speeches and practices of some stakeholders, selected according to their influence on the way to conceive and then practice social acceptance, and according to the risks of bias and confusion between assumptions, hypothesis and evidences. Such guidelines are likely to contribute to the social and academic debates in relation to the issues of management and public decision-making with respect to major projects.