The term "Big Mouth" in Kdrama usually refers to the popular legal drama Big Mouth. In this series, the protagonist, Park Chang-ho, is often referred to as the "Big Mouth". This nickname is given to him because of his reputation as a skilled lawyer, though he is later revealed to be a con artist.
However, the term "Big Mouth" can also be used more broadly to describe any character who is known for their talkativeness or tendency to exaggerate. For example, in the drama Strong Woman Do Bong-soon, Do Bong-soon's friend, In Gook-doo, could be considered a "Big Mouth" because he is often loud and boisterous, and prone to making grandiose statements.
Ultimately, the "real Big Mouth" in any Kdrama depends on the specific context and the character's actions and personality.
