This paper suggests that ambiguity is perhaps not so much lexical as functional, as can be observed through the small-scale investigation of a polysemous legal adjective of English used in a single modifier-head structure. A description of how functional overlaps may cause ambiguity is illustrated by the results of a corpus-based study, where ambiguity-solving is investigated through lexico-grammatical analysis and translation into French. The paper concludes with the proposition that, within legal language itself, adjectives may be said to have field-specific conceptual centres and metaphoric extensions, which suggests in turn that bilingual lexicography could benefit from a computerized representation based on this approach.