deceit vs illusion

deceit and illusion both are nouns.

Word	Noun	Adjective	Verb	Adverb
deceit	Yes	No	No	No
illusion	Yes	No	No	No

As nouns, illusion is a hyponym of deceit; that is, illusion is a word with a more specific, narrower meaning than deceit:

deceit (noun)	illusion (noun)
the act of deceiving	the act of deluding; deception by creating illusory ideas
the quality of being fraudulent	an illusory feat; considered magical by naive observers
a misleading falsehood	something many people believe that is false
	an erroneous mental representation