irritant vs infliction

irritant and infliction both are nouns.

Word	Noun	Adjective	Verb	Adverb
irritant	Yes	No	No	No
infliction	Yes	No	No	No

As nouns, infliction is a hypernym of irritant; that is, infliction is a word with a broader meaning than irritant:

irritant: something that causes irritation and annoyance
infliction: something or someone that causes trouble; a source of unhappiness

Other hypernyms of irritant include annoyance, bother, botheration, nuisance, pain, pain in the ass, pain in the neck.

irritant (noun)	infliction (noun)
something that causes irritation and annoyance	the act of imposing something (as a tax or an embargo)
	an act causing pain or damage
	something or someone that causes trouble; a source of unhappiness