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.
Depending on whether your device supports 3D Touch or Haptic Touch, you will see the corresponding option in this menu.
Source: https://www.devicemag.com/how-to-adjust-touch-sensitivity-on-iphone-x/