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.
In addition, all of these selections come in audio-form with better-than-average narration; something absolutely critical to a good audiobook experience.
Source: https://ufvcascade.ca/book-recommendations-for-the-lifelong-learner/