In contrast with various Austronesian languages (especially Formosan, Philippine, Polynesian) for which lexical roots are claimed to be functionally unspecified or precategorial, lexical bases in Nêlêmwa (New Caledonia) evidence a clear noun/verb opposition, identifiable by distinctive morphosyntactic features, except for some 5% fluid bases which can be nouns or verbs without any derivation. Beyond their prototypical functions, nouns, verbs and their subcategories display some functional flexibility in Nêlêmwa; it thus stands midway between flexible and rigid languages. Yet categorial flexibility is asymmetrical, nouns are the most flexible and may be recategorised in relation to their propositional operation and syntactic function, giving rise to hybrid lexico-syntactic words. Nêlêmwa data will be compared and put into perspective with data from other Austronesian languages.