Something or someone that is mythical exists only in myths and is therefore imaginary. the Hydra, the mythical beast that had seven or more heads
{s} of or pertaining to a myth; described in a legendary story; imaginary, fictional
based on or told of in traditional stories; lacking factual basis or historical validity; "mythical centaurs"; "the fabulous unicorn"
Of or relating to myths; described in a myth; of the nature of a myth; fabulous; imaginary; fanciful
If you describe something as mythical, you mean that it is untrue or does not exist. the American West, not the mythical, romanticized West of cowboys and gunslingers, but the real West
If you describe someone or something as mythic, you mean that they have become very famous or important. a team whose reputation has achieved mythic proportions