EN
The present paper deals with lexicality and gramaticality and the criteria which allow to decide whether a linguistic unit belongs to the field of grammar or not. It could be shown that the morfological distinction, as it appears for instance in English, French and Polish, between a special kind of adjectives and adverbs does not give rise to different parts of speach but has to be considered as being the result of a grammatical opposition, namely adverbality and adnominality.