witticism vs irony

witticism and irony both are nouns.

Word	Noun	Adjective	Verb	Adverb
witticism	Yes	No	No	No
irony	Yes	No	No	No

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

witticism: a message whose ingenuity or verbal skill or incongruity has the power to evoke laughter
irony: witty language used to convey insults or scorn

witticism (noun)	irony (noun)
a message whose ingenuity or verbal skill or incongruity has the power to evoke laughter	incongruity between what might be expected and what actually occurs
	a trope that involves incongruity between what is expected and what occurs
	witty language used to convey insults or scorn