head game vs illusion

head game and illusion both are nouns.

Word	Noun	Adjective	Verb	Adverb
head game	Yes	No	No	No
illusion	Yes	No	No	No

As nouns, head game and illusion are synonyms defined as:

head game and illusion: the act of deluding; deception by creating illusory ideas

Other synonyms of head game include delusion.

head game (noun)	illusion (noun)
the act of deluding; deception by creating illusory ideas	the act of deluding; deception by creating illusory ideas
	an illusory feat; considered magical by naive observers
	something many people believe that is false
	an erroneous mental representation