blather vs maunder

blather is a noun but maunder is not a noun.

Word	Noun	Adjective	Verb	Adverb
blather	Yes	No	Yes	No
maunder	No	No	Yes	No

As verbs, maunder is a hypernym of blather; that is, maunder is a word with a broader meaning than blather:

Other hypernyms of blather include blab, blabber, chatter, clack, gabble, gibber, palaver, piffle, prate, prattle, tattle, tittle-tattle, twaddle.

blather (noun)	maunder (noun)
foolish gibberish

blather (verb)	maunder (verb)
to talk foolishly	talk indistinctly; usually in a low voice
	speak (about unimportant matters) rapidly and incessantly
	wander aimlessly