This article considers metaphor and metonymy in verbs belonging to the semantic domain of "percussion and impact" (P/I): that is, verbs whose meaning centres around the idea "hit". It proposes two new categories for the understanding of metaphor and metonymy, specifically in their relation to conventionalization: hypermetonymy and hypermetaphor. Hypermetonymies are originally metonymic semantic extensions which have been generalized and conventionalized so as to no longer depend on the presence of percussion or impact in their referent: their contexts of use have "overshot" the domains of their original appropriateness. Hypermetaphors, likewise, are originally metaphorical applications of a percussion/impact expression in which no connection to percussion or impact is any longer relevant, but which continue to convey the meaning originally instantiated by the metaphor. The importance of metonymy or metaphor as the original explanation of a semantic extension thus does not disappear when the extension becomes conventionalized, and the lines between metonymy and metaphor are not blurred solely in virtue of the fact that the original motivation of a meaning is no longer present. Metaphor and metonymy remain essentially separate, even under conventionalization, contrary to the claims of certain analyses. (Goossens 1990, 1995).