rumour vs scuttlebutt

rumour and scuttlebutt both are nouns.

Word	Noun	Adjective	Verb	Adverb
rumour	Yes	No	Yes	No
scuttlebutt	Yes	No	No	No

As nouns, scuttlebutt is a hypernym of rumour; that is, scuttlebutt is a word with a broader meaning than rumour:

rumour: gossip (usually a mixture of truth and untruth) passed around by word of mouth
scuttlebutt: a report (often malicious) about the behavior of other people

Other hypernyms of rumour include comment, gossip.

rumour (noun)	scuttlebutt (noun)
gossip (usually a mixture of truth and untruth) passed around by word of mouth	a report (often malicious) about the behavior of other people

rumour (verb)	scuttlebutt (verb)
tell or spread rumors