名詞 illusion:

1. an erroneous mental representation
   同義詞：semblance
2. something many people believe that is false
   同義詞：fantasy, phantasy, fancy
3. the act of deluding; deception by creating illusory ideas
   同義詞：delusion, head game
4. an illusory feat; considered magical by naive observers
   同義詞：magic trick, conjuring trick, trick, magic, legerdemain, conjuration, thaumaturgy, deception

1. A mirage is an optical illusion.
   海市蜃樓是一種視錯覺。
2. I thought I saw a ghost but it was just an optical illusion.
   我以為我看見鬼了，其實只是一種幻覺。
3. I was under the illusion that he was honest until he was caught stealing some money.
   他偷錢當場被人抓住，在此之前我一直誤以為他是個老實人。
4. He cherished the illusion that she loved him, but he was wrong.
   他抱有她愛他的幻覺，但他錯了。

il.lu.sion

n.（名詞）

An erroneous perception of reality.
錯覺，假象：對現(xiàn)實錯誤的看法
An erroneous concept or belief.
錯誤的觀念：錯誤的觀念或信仰
The condition of being deceived by a false perception or belief.
被錯覺蒙蔽的現(xiàn)象：被錯誤看法或信仰欺騙后所呈現(xiàn)的狀態(tài)
Something, such as a fantastic plan or desire, that causes an erroneous belief or perception.
幻覺：導致錯誤的信仰或觀點的錯誤根源，例如一個古怪的計劃或欲望
Illusionism in art.
魔術手法：藝術上的錯覺藝術手法
A fine transparent cloth, used for dresses or trimmings.
絹網(wǎng)，薄紗：用于衣服或裝飾的透明的高質量的布

來源：
Middle English
中古英語
from Old French
源自 古法語
from Late Latin illôsiô illôsiôn-
源自 后期拉丁語 illôsiô illôsiôn-
from Latin [a mocking, irony]
源自 拉丁語 [愚弄，命運的嘲弄]
from illôsus [past participle of] illôdere [to mock]
源自 illôsus [] illôdere的過去分詞 [愚弄]
in- [against] * see in- 2
in- [反對] *參見 in-2
lôdere [to play] * see leid-
lôdere [玩弄] *參見 leid-

【引伸】
illu.sional 或
illu.sionar.y
illu.sionless
adj.（形容詞）