blab vs piffle

blab is not a noun while piffle is a noun.

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

As verbs, blab and piffle are synonyms defined as:

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

blab (noun)	piffle (noun)
	trivial nonsense

blab (verb)	piffle (verb)
divulge confidential information or secrets	act in a trivial or ineffective way
speak (about unimportant matters) rapidly and incessantly	speak (about unimportant matters) rapidly and incessantly