rudeness vs discourtesy

rudeness and discourtesy both are nouns.

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

As nouns, rudeness and discourtesy are synonyms defined as:

rudeness (noun)	discourtesy (noun)
a manner that is rude and insulting	a lack of politeness; a failure to show regard for others; wounding the feelings of others
a wild or unrefined state	a manner that is rude and insulting
	an expression of lack of respect