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 I showed you the French sentence “Le professeur est insidieux,” you would probably be able to guess its meaning “The professor is insidious.”
Source: https://thecrimsonwhite.com/109217/opinion/letter-to-the-editor-dispelling-language-learning-myths/