A fantasy is a pleasant situation or event that you think about and that you want to happen, especially one that is unlikely to happen.

You can refer to a story or situation that someone creates from their imagination and that is not based on reality as fantasy .

Fantasy is the activity of imagining things.

Fantasy football, baseball, or another sport is a game in which players choose an imaginary team and score points based on the actual performances of the members of their team in real games.