Discourse is the locus where the interlocutors negotiate the meaning of lexical items. This paper aims to develop a multifuctional profile of though as a discourse marker specially through the study of what functions a discourse marker though has. It is shown that though as a discourse marker is syntactically free and usually enclitic. Its basic use is to introduce a proposition that is contrary to expectation. It signals that the speaker is engaged in a particular speech act, especially of a face-threatening type, such as contradicting, correcting, or disagreeing with the previous speaker. It can serve function of introducing a new topic or subtopic as Barth-Weingarten and Couper-Kuhlen (2002) suggested as the function of the final though. In addition, the syntactic and semantic change of though is traced in light of grammaticalization. It claims that in the course of grammaticalization of though, some mechanisms are employed such as subjectification, generalization, persistence, divergence, and layering