The method of estimating the relevance of a document with respect to a concept comprises calculating (32) a relevance function of the concept with respect to said document on the basis of a known predetermined semantic neighborhood of the concept. It further comprises calculating an ambiguity function of said concept in said document, which ambiguity function is different from the relevance function, said calculation being an estimation based on the presence in the document of different meanings of the concept. The method follows on from a preliminary step of detecting ambiguous concepts in a database.