If you describe something as illusory, you mean that although it seems true or possible, it is in fact false or impossible.
例句
His freedom is illusory.他的自由是虛幻的。...the illusory nature of nationhood.國家的虛假本質
英漢詞典釋義
adj.
<正>貌似真實的;虛幻的
It seemed to an idealistic and illusory dream.那似乎是個不切實際、理想主義的美夢。
英英詞典釋義
Adjective
1. based on or having the nature of an illusion;
"illusive hopes of of finding a better job""Secret activities offer presidents the alluring but often illusory promise that they can achieve foreign policy goals without the bothersome debate and open decision that are staples of democracy"