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.
Alternatively, look towards apps like BlackMagic's DaVinci Resolve, which is free on the iPad (as well as on Mac or PC), with only some advanced features requiring a paid upgrade.
Source: https://www.cnet.com/tech/mobile/how-to-make-beautiful-family-holiday-movies-with-your-phone/