The best replacement for illusion is delusion.

The best alternatives to illusion are rated as following:
★★★★★  delusion
★★★★★  allusion
★★★★★  reality
★★★★  hallucination
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★  magic
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★  telekinesis dcuo
★  telekinesis
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★  conjuration
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  reality death of a salesman
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  verizon samsung galaxy legend
  perception
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  hallucinations
  lg enlighten
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Your alternative for illusion is not listed? Suggest!
Speaking about illusion, one probably shouldn't forget about sneak.

Other search terms related to illusion and their ratings are:
★★★★★ sneak
You have in mind a companion for illusion and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of illusion in all years. Click on graph for more.
illusion
delusion
allusion