irony vs indeed

irony is a noun but indeed is not a noun.

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

irony (noun)	indeed (noun)
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

irony (adverb)	indeed (adverb)
	(used as an interjection) an expression of surprise or skepticism or irony etc.
	in truth (often tends to intensify)