Definition of "subtext"

The word dick has meant penis since the 1890s, but Chester Gould’s private detective “Dick Tracy” has no puerile subtext related to this word.

2011, Patrick Spedding, James Lambert, “Fanny Hill, Lord Fanny, and the Myth of Metonymy”, in Studies in Philology, volume 108, number 1, page 113

While his major plays appear on the surface to have little plot, their subtext is full of overheated romance and melodrama.

2012 July 27, Jason Zinoman, “Chekhov's Banana Peel”, in Slate‎