colouring has 7 distinct synonyms spread across 3 of its 3 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a digestible substance used to give color to food
“food color made from vegetable dyes”
a visual attribute of things that results from the light they emit or transmit or reflect
“a white color is made up of many different wavelengths of light”
the act or process of changing the color of something
Synonyms, antonyms and the broader and narrower relations for colouring come from Princeton University’s WordNet. Full sources and licences.