mirage

1. N-COUNT A mirage is something that you see when it is extremely hot, for example in the desert, and which appears to be quite near but is actually a long way away or does not really exist. 海市蜃樓; 幻境

It hovered before his eyes like the mirage of an oasis. 它在他眼前晃動，好像海市蜃樓裡的綠洲。

2. N-COUNT If you describe something as a mirage, you mean that it is not real or true, although it may seem to be. 幻想; 妄想[usu sing]

The girl was a mirage, cast up by his troubled mind. 那個女孩是他的幻覺，是他混亂的頭腦中妄想出來的。