An illusion is something that isn't real. It may look real, but it's actually fake — just a crafty construction or fantasy. Like the old rabbit-out-of-the-hat trick practiced by magicians around the globe.

An illusion is an act of deception. Some optical illusions are pretty cool to watch, but an illusion can also point to an erroneous belief or false perception of reality, which is where you start getting into hallucination territory — seeing things that aren't there. You can give the illusion that you’re fascinated by your professor’s lecture by chewing on your pencil, furrowing your brow, and making sure to nod enthusiastically every so often.

Definitions of illusion
  1. noun
    an erroneous mental representation
    synonyms: semblance
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    apparition, fantasm, phantasm, phantasma, phantom, shadow
    something existing in perception only
    the apparent enlargement of a bright object when viewed against a dark background
    phantom limb
    the illusion that a limb still exists after it has been amputated
    UFO, flying saucer, unidentified flying object
    an (apparently) flying object whose nature is unknown; especially those considered to have extraterrestrial origins
    Flying Dutchman
    a phantom ship that is said to appear in storms near the Cape of Good Hope
    ghost, shade, specter, spectre, spook, wraith
    a mental representation of some haunting experience
    type of:
    a mental representation
  2. noun
    an illusory feat; considered magical by naive observers
    synonyms: conjuration, conjuring trick, deception, legerdemain, magic, magic trick, thaumaturgy, trick
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    card trick
    a trick performed with playing cards
    prestidigitation, sleight of hand
    manual dexterity in the execution of tricks
    type of:
    the act of presenting a play or a piece of music or other entertainment
  3. noun
    something many people believe that is false
    “they have the illusion that I am very wealthy”
    synonyms: fancy, fantasy, phantasy
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    an impracticable and illusory idea
    ignis fatuus, will-o'-the-wisp
    an illusion that misleads
    wishful thinking
    the illusion that what you wish for is actually true
    type of:
    an incorrect conception
  4. noun
    the act of deluding; deception by creating illusory ideas
    synonyms: delusion, head game
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    type of:
    deceit, deception, dissembling, dissimulation
    the act of deceiving
Commonly confused words

allusion / illusion / delusion

Novelists, magicians, and other tricksters keep these words busy. Novelists love an allusion, an indirect reference to something like a secret treasure for the reader to find; magicians heart illusions, or fanciful fake-outs; but tricksters suffer from delusions, ideas that have no basis in reality.

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