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.
Steve’s favourite fantasy was to own a big house and a flashy car.
sexual fantasies
fantasy world
She retreated into a fantasy world, where she could be anything she wanted.
[I, T] ~ (about sth) |~ (that…) to imagine that you are doing sth that you would like to do, or that sth that you would like to happen is happening, even though this is very unlikely 想象；幻想；做白日梦
He sometimes fantasized about winning the gold medal.
他有时幻想赢得金牌的情景。