clack vs blab

clack is a noun but blab is not a noun.

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

As verbs, clack and blab are synonyms defined as:

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

clack (noun)	blab (noun)
a simple valve with a hinge on one side; allows fluid to flow in only one direction
a sharp abrupt noise as if two objects hit together; may be repeated

clack (verb)	blab (verb)
speak (about unimportant matters) rapidly and incessantly	divulge confidential information or secrets
make a clucking sounds, characteristic of hens	speak (about unimportant matters) rapidly and incessantly
make a rattling sound