informal vs formality

informal is not a noun while formality is a noun.

Word	Noun	Adjective	Verb	Adverb
informal	No	Yes	No	No
formality	Yes	No	No	No

informal (noun)	formality (noun)
	compliance with formal rules
	a manner that strictly observes all forms and ceremonies
	a requirement of etiquette or custom

informal (adjective)	formality (adjective)
not formal
used of spoken and written language
having or fostering a warm or friendly and informal atmosphere
not officially recognized or controlled