twaddle vs blab

twaddle is a noun but blab is not a noun.

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

As verbs, twaddle and blab are synonyms defined as:

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

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

twaddle (noun)	blab (noun)
pretentious or silly talk or writing

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