blab vs gibber

blab is not a noun while gibber is a noun.

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

As verbs, blab and gibber are synonyms defined as:

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

blab (noun)	gibber (noun)
	unintelligible talking

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