The opposite of new is usually "old."
Some variations are outmoded, outdated, or archaic.
New.
The opposite of a new thing is an old thing.
New and Knew
New or young is opposite to old.
The opposite of old is new, and the homophone for new that means "had an understanding of" is "knew." There are two more homophones for new: "gnu" and "nu."new, knew
The opposite could be new, recent, modern, or young.
NEW
The opposite of a full moon is a new moon.
opposite flow
The opposite could be new, recent, modern, or young.
Ancient
new