A five letter word that is the opposite of the word "gradual" and contains a second letter of "l" is a popular word game answer. The five letter word being sought is "fleet."
Polite is a 6-letter word that is the opposite of rude.
decayed
scent
Envelope.
Running
running
The word is roundest.
stopping
Teenager
The opposite of not walking is walking.
Imprison is a word which has the opposite to liberate and has eight letters
Stopping
Shutting
approach, increase
The opposite of not opening is opening. Eight-letter synonyms for opening, depending on context, include clearing, unlacing, exposing, starting
The opposite for walk is stay(as in standing still) or not walk