chilli pepper vs cayenne pepper

chilli pepper and cayenne pepper both are nouns.

Word	Noun	Adjective	Verb	Adverb
chilli pepper	Yes	No	No	No
cayenne pepper	Yes	No	No	No

As nouns, chilli pepper and cayenne pepper are synonyms defined as:

chilli pepper and cayenne pepper: plant bearing very hot and finely tapering long peppers; usually red

Other synonyms of chilli pepper include Capsicum annuum longum, cayenne, chili pepper, jalapeno, long pepper.

chilli pepper (noun)	cayenne pepper (noun)
plant bearing very hot and finely tapering long peppers; usually red	ground pods and seeds of pungent red peppers of the genus Capsicum
	a long and often twisted hot red pepper
	plant bearing very hot and finely tapering long peppers; usually red