The question of why, in some cases, French adjectives that are used attributively in an NP cannot be predicative of the head N of the same NP is usually approached from the point of view of the adjective alone. The aim of this article is to show that, for some NPs, this impossibility can only be explained by considering the properties of both the head N and its attributive adjective. For example, in an NP such as l’instigateur probable de l’attentat, which has a relational N as its head, the attributive adjective probable resists the predicative function because probable does not contribute to the description of the individual the NP refers to, as becomes clear in the paraphrase celui qui a probablement suscité l’attentat.