blabbermouth vs gossipmonger

blabbermouth and gossipmonger both are nouns.

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

As nouns, gossipmonger is a hypernym of blabbermouth; that is, gossipmonger is a word with a broader meaning than blabbermouth:

blabbermouth: someone who gossips indiscreetly
gossipmonger: a person given to gossiping and divulging personal information about others

Other hypernyms of blabbermouth include gossip, gossiper, newsmonger, rumormonger, rumourmonger.

blabbermouth (noun)	gossipmonger (noun)
someone who gossips indiscreetly	a person given to gossiping and divulging personal information about others