Secondary Colours of Jason 'J.D.' Dean in Heathers (1989)
One of the most iconic aspects of the Heathers movie is the distinctive colour palettes for each character. J.D.’s primary colour is black, which initially seems like it means ‘he wears black because he’s cool’. Then you realise, 'he wears black because he’s actually the murderous villain of the piece’.
J.D. also has a good game on his secondary colours. He’s usually in three layers: the black trenchcoat, a coloured undershirt, and a men’s tank top. In his first appearance, that’s a green undershirt. Green is also Heather Duke’s (initial) colour. Green is a secondary colour, unlike the other three Heathers; green signifies Heather Duke’s envy and illness (bulimia). For J.D., the green seems to mean that he wants something - and at that point in the story, I don’t think J.D. himself is certain of what that is.
Green also matches Christian Slater’s eye colour, so, good fashion choice.