cosiness vs cosy

cosiness and cosy both are nouns.

Word	Noun	Adjective	Verb	Adverb
cosiness	Yes	No	No	No
cosy	Yes	Yes	No	No

cosiness (noun)	cosy (noun)
a state of warm snug comfort	a padded cloth covering to keep a teapot warm

cosiness (adjective)	cosy (adjective)
	enjoying or affording comforting warmth and shelter especially in a small space
	suggesting connivance
	having or fostering a warm or friendly and informal atmosphere