impoliteness vs discourtesy

impoliteness and discourtesy both are nouns.

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

As nouns, discourtesy is a hypernym of impoliteness; that is, discourtesy is a word with a broader meaning than impoliteness:

Other hypernyms of impoliteness include rudeness.

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