least
Happy.
sweet
Polite is a 6-letter word that is the opposite of rude.
stop or halt is a four letter word meaning the opposite of go.
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."
A five letter word for the opposite of lower is upper.
A five letter word meaning the opposite of hurry would be dally. There may well be others
night
plain
Sharp
awake
fresh
giant
small
least
Happy.