red pepper vs hot pepper

red pepper and hot pepper both are nouns.

Word	Noun	Adjective	Verb	Adverb
red pepper	Yes	No	No	No
hot pepper	Yes	No	No	No

As nouns, hot pepper is a hypernym of red pepper; that is, hot pepper is a word with a broader meaning than red pepper:

red pepper (noun)	hot pepper (noun)
ground pods and seeds of pungent red peppers of the genus Capsicum	any of various pungent capsicum fruits
very hot red peppers; usually long and thin; some very small	plant bearing very hot medium-sized oblong red peppers; grown principally in the Gulf Coast states for production of hot sauce