gibber vs blab

gibber is a noun but blab is not a noun.

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

As verbs, gibber and blab are synonyms defined as:

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

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

gibber (noun)	blab (noun)
unintelligible talking

gibber (verb)	blab (verb)
speak (about unimportant matters) rapidly and incessantly	divulge confidential information or secrets
chatter inarticulately; of monkeys	speak (about unimportant matters) rapidly and incessantly