"The opposite of easy is difficult."
Translation:La malo de facila estas malfacila.
Sometimes the hardest part is remembering what the English opposite word is... facila and malfacila are much "non-difficulter"
One of the options I got was "La malo de facila estas progreso". It certainly is!
Could you say "La malo de facila malfacilas"? It seems to follow the rules I've been taught so far, but it just seems wrong somehow...
In this sentence, "facila" and "malfacila" are quoted text, even if quotes are not used. You cannot change it into a verb.
When you add a verb ending to an adjective, it means "to be X". So La malo de facila malfacilas means "The opposite of easy is hard [to learn, to know, etc.]".