This article focuses on ongoing work done for Portuguese concerning the phenomenon of lexical co-occurrence known as collocation (cf. Cruse, 1986, inter al.). Instances of the syntactic variety formed by noun plus adjective have been especially observed. Collocational instances are not lexical entries, and thus should not be stored in the lexicon as multiword lexical units. Their processing can be conceived through relations linking the lexical components. Mechanisms for dealing with the collocation-hood of the expressions are required to be included in the systems, topographically, in their lexical modules. Lexical databases like wordnets, with a general architecture typically structured on semantic relations, make room for the specification of this phenomenon. This can be handled through the definition of ad-hoc relations expressing the different semantic effects the adjectival modification bring to nominal phrases, collocationally. 1