rumourmonger vs tattler

rumourmonger and tattler both are nouns.

Word	Noun	Adjective	Verb	Adverb
rumourmonger	Yes	No	No	No
tattler	Yes	No	No	No

As nouns, tattler is a hyponym of rumourmonger; that is, tattler is a word with a more specific, narrower meaning than rumourmonger:

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

Other hyponyms of rumourmonger include cat, scandalmonger, blabbermouth, talebearer, taleteller, tattletale, telltale, yenta.

rumourmonger (noun)	tattler (noun)
a person given to gossiping and divulging personal information about others	any of several long-legged shorebirds having a loud whistling cry
	someone who gossips indiscreetly