mirthful vs funny

mirthful is not a noun while funny is a noun.

Word	Noun	Adjective	Verb	Adverb
mirthful	No	Yes	No	No
funny	Yes	Yes	No	No

As adjectives, mirthful and funny are synonyms defined as:

Other synonyms of mirthful include amusing, comic, comical, laughable, risible.

mirthful (noun)	funny (noun)
	an account of an amusing incident (usually with a punch line)

mirthful (adjective)	funny (adjective)
arousing or provoking laughter	arousing or provoking laughter
full of or showing high-spirited merriment	experiencing odd bodily sensations
	not as expected
	beyond or deviating from the usual or expected