discourtesy vs curtness

discourtesy and curtness both are nouns.

Word	Noun	Adjective	Verb	Adverb
discourtesy	Yes	No	No	No
curtness	Yes	No	No	No

As nouns, curtness is a hyponym of discourtesy; that is, curtness is a word with a more specific, narrower meaning than discourtesy:

discourtesy (noun)	curtness (noun)
a lack of politeness; a failure to show regard for others; wounding the feelings of others	an abrupt discourteous manner
a manner that is rude and insulting
an expression of lack of respect