chili pepper vs chilly

chili pepper and chilly both are nouns.

Word	Noun	Adjective	Verb	Adverb
chili pepper	Yes	No	No	No
chilly	Yes	Yes	No	No

As nouns, chili pepper and chilly are synonyms defined as:

chili pepper and chilly: very hot and finely tapering pepper of special pungency

Other synonyms of chili pepper include chile, chili, chilli.

chili pepper (noun)	chilly (noun)
very hot and finely tapering pepper of special pungency	very hot and finely tapering pepper of special pungency
plant bearing very hot and finely tapering long peppers; usually red

chili pepper (adjective)	chilly (adjective)
	appreciably or disagreeably cold
	not characterized by emotion
	lacking warmth of feeling