cosy vs informal

cosy is a noun but informal is not a noun.

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

As adjectives, cosy and informal are synonyms defined as:

cosy and informal: having or fostering a warm or friendly and informal atmosphere

Other synonyms of cosy include cozy, intimate.

cosy (noun)	informal (noun)
a padded cloth covering to keep a teapot warm

cosy (adjective)	informal (adjective)
enjoying or affording comforting warmth and shelter especially in a small space	not formal
suggesting connivance	used of spoken and written language
having or fostering a warm or friendly and informal atmosphere	having or fostering a warm or friendly and informal atmosphere
	not officially recognized or controlled