Synonyms that are in the dictionary are marked in green. Synonyms that are not in the dictionary are marked in red.
Antonyms that are in the dictionary are marked in green. Antonyms that are not in the dictionary are marked in red.
For example, if you come across text that is not legible, the Magnifier app can apply filters, add more light from the LED flash, and adjust brightness and contrast levels to make the text readable.
Source: https://www.slashgear.com/1409409/apple-point-speak-feature-explained/