defame vs badmouth

defame and badmouth both are verbs.

Word	Noun	Adjective	Verb	Adverb
defame	No	No	Yes	No
badmouth	No	No	Yes	No

As verbs, badmouth is a hyponym of defame; that is, badmouth is a word with a more specific, narrower meaning than defame:

defame: charge falsely or with malicious intent; attack the good name and reputation of someone
badmouth: speak unfavorably about

Other hyponyms of defame include assassinate, libel, drag through the mud, malign, traduce.

defame (verb)	badmouth (verb)
charge falsely or with malicious intent; attack the good name and reputation of someone	speak unfavorably about