In scriptwriting, subtext refers to the implicit emotional intent or significance which underlies things such as words spoken or physical actions that are visible on stage/screen. It is what makes scenes richer or more difficult to interpret in terms of what particular characters want/do not want when we watch them interact.
The proficient use of undercurrent in conversation, gestures, and scenario to communicate unvoiced tensions or hidden stories is a great talent. Subtext provides an opportunity for authors to develop open-mindedness, mystery, and significance in the narrative, thus involving the audience in the story more actively.
Delving deeper beneath the surface of the dialogue gives characters more depth and truth, thus rendering the script more complete owing to its orientation to varied dimensions of human conduct and feeling.
Following video by StudioBinder explains about “Subtexts – The Secret to Writing What’s Under the Surface”