courtesy vs manner

courtesy and manner both are nouns.

Word	Noun	Adjective	Verb	Adverb
courtesy	Yes	No	No	No
manner	Yes	No	No	No

As nouns, manner is a hypernym of courtesy; that is, manner is a word with a broader meaning than courtesy:

Other hypernyms of courtesy include personal manner.

courtesy (noun)	manner (noun)
a courteous or respectful or considerate act	a way of acting or behaving
a courteous manner	how something is done or how it happens
a courteous or respectful or considerate remark	a kind