The present paper illustrates the fuzzy limits between modality markers and discourse markers by analysing the different uses based on the word clar ‘clear’ in oral Catalan. Clar is lexically described as an adjective, but it has developed different functions in various syntactic and pragmatic contexts. In the adverbial and the interjective uses, (és) clar (que) ‘it is clear that’ is a modality marker indicating certainty and shared knowledge. As a conjunction, clar que has developed a concessive meaning (‘but, nevertheless’). When (és) clar acts as a discourse marker (i.e. introducing an utterance) it can be an effective mitigation device used to soften a potentially face-threatening act by showing agreement, solidarity and co-orientation in argumentation. Its basic modal meaning (‘it is obvious’, ‘I agree’), shared to a different extent with the adverb and the interjection, tends to be enriched with structural functions, as turn initiator or boundary marker inside a turn. To account for the polyfunctionality of (és) clar (que), a cline from prototypically modal functions to prototypically structural functions is proposed—the intermediate area being occupied by the marker use.