Noun. (plural nekomimi or nekomimis). ( 1 chiefly Japanese fiction) A fictional character who has cat ears on top of the head of an otherwise human body, and possibly other feline characteristics as well, such as a tail.oun. (plural nekomimi or nekomimis). ( 1 chiefly Japanese fiction) A fictional character who has cat ears on top of the head of an otherwise human body, and possibly other feline characteristics as well, such as a tail.