slander vs libel

slander and libel both are nouns.

Word	Noun	Adjective	Verb	Adverb
slander	Yes	No	Yes	No
libel	Yes	No	Yes	No

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

slander: charge falsely or with malicious intent; attack the good name and reputation of someone
libel: print slanderous statements against

Other hyponyms of slander include assassinate, badmouth, drag through the mud, malign, traduce.

slander (noun)	libel (noun)
an abusive attack on a person's character or good name	a false and malicious publication printed for the purpose of defaming a living person
words falsely spoken that damage the reputation of another	the written statement of a plaintiff explaining the cause of action (the defamation) and any relief he seeks

slander (verb)	libel (verb)
charge falsely or with malicious intent; attack the good name and reputation of someone	print slanderous statements against