tattletale vs blabbermouth

tattletale and blabbermouth both are nouns.

Word	Noun	Adjective	Verb	Adverb
tattletale	Yes	No	No	No
blabbermouth	Yes	No	No	No

As nouns, tattletale and blabbermouth are synonyms defined as:

Other synonyms of tattletale include talebearer, taleteller, tattler, telltale.

tattletale (noun)	blabbermouth (noun)
someone who gossips indiscreetly	someone who gossips indiscreetly