witticism vs subject matter

witticism and subject matter both are nouns.

Word	Noun	Adjective	Verb	Adverb
witticism	Yes	No	No	No
subject matter	Yes	No	No	No

As nouns, subject matter is a hypernym of witticism; that is, subject matter is a word with a broader meaning than witticism:

witticism: a message whose ingenuity or verbal skill or incongruity has the power to evoke laughter
subject matter: content communicating a message; what something is about

Other hypernyms of witticism include content, message, substance.

witticism (noun)	subject matter (noun)
a message whose ingenuity or verbal skill or incongruity has the power to evoke laughter	content communicating a message; what something is about