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(cuò)覺(jué)。
2. I thought I saw a ghost but it was just an optical illusion.
   我以為我看見(jiàn)鬼了，其實(shí)只是一種幻覺(jué)。
3. I was under the illusion that he was honest until he was caught stealing some money.
   他偷錢(qián)當(dāng)場(chǎng)被人抓住，在此之前我一直誤以為他是個(gè)老實(shí)人。
4. He cherished the illusion that she loved him, but he was wrong.
   他抱有她愛(ài)他的幻覺(jué)，但他錯(cuò)了。

il.lu.sion

n.（名詞）

An erroneous perception of reality.
錯(cuò)覺(jué)，假象：對(duì)現(xiàn)實(shí)錯(cuò)誤的看法
An erroneous concept or belief.
錯(cuò)誤的觀念：錯(cuò)誤的觀念或信仰
The condition of being deceived by a false perception or belief.
被錯(cuò)覺(jué)蒙蔽的現(xiàn)象：被錯(cuò)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(jué)：導(dǎo)致錯(cuò)誤的信仰或觀點(diǎn)的錯(cuò)誤根源，例如一個(gè)古怪的計(jì)劃或欲望
Illusionism in art.
魔術(shù)手法：藝術(shù)上的錯(cuò)覺(jué)藝術(shù)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(zhì)量的布

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

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