blabbermouth vs rumormonger

blabbermouth and rumormonger both are nouns.

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

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

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

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

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