prattle vs blab

prattle is a noun but blab is not a noun.

Word	Noun	Adjective	Verb	Adverb
prattle	Yes	No	Yes	No
blab	No	No	Yes	No

As verbs, prattle and blab are synonyms defined as:

prattle and blab: speak (about unimportant matters) rapidly and incessantly

Other synonyms of prattle include blabber, chatter, clack, gabble, gibber, maunder, palaver, piffle, prate, tattle, tittle-tattle, twaddle.

prattle (noun)	blab (noun)
idle or foolish and irrelevant talk

prattle (verb)	blab (verb)
speak (about unimportant matters) rapidly and incessantly	divulge confidential information or secrets
	speak (about unimportant matters) rapidly and incessantly