malicious gossip vs scuttlebutt

malicious gossip and scuttlebutt both are nouns.

Word	Noun	Adjective	Verb	Adverb
malicious gossip	Yes	No	No	No
scuttlebutt	Yes	No	No	No

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

malicious gossip: disgraceful gossip about the private lives of other people
scuttlebutt: a report (often malicious) about the behavior of other people

Other hypernyms of malicious gossip include comment, gossip.

malicious gossip (noun)	scuttlebutt (noun)
disgraceful gossip about the private lives of other people	a report (often malicious) about the behavior of other people