Being extant means to exist or to be present. The opposite of being extant can be described through antonyms such as non-existing, extinct, vanished, or defunct. A non-existing thing or concept has not yet come into being. Extinct species, on the other hand, are no longer present or alive. The term vanished denotes something that was previously existing but has now disappeared, whereas defunct refers to something that once existed but is no longer operational. Thus, the antonyms for being extant can indicate the absence, loss, or cessation of something that was once present or potentially present.