This paper studies the notion of implicitness in Diplomatic Discourse, a term referring to strategies and forms of covering up non shareable information. The research combines insights from functional linguistics, discourse semantics, and lexicogrammatical theories and employs Grammatical Metaphor in order to approach implicit discourse from a multidisciplinary perspective. Based on corpora, having compiled Chinese data of Diplomatic Discourse and their English translation, the paper explores the emergence of Grammatical Metaphors and the way they emphasize certain elements of discourse, especially within translated versions. The final aim of the author is to offer a three-fold model appropriate for translating Diplomatic Discourse.