Noun
2. character assassination
3. calumny
4. libel
6. malicious gossip
10. vilification
12. obloquy
13. lie
14. slur
15. smear
16. false accusation
18. bad-mouthing
19. smack talk
20. contumely
Verb
22. blacken someone's name
23. tell lies about
26. libel
27. smear
28. cast aspersions on
29. spread scandal about
30. besmirch
31. tarnish
32. taint
33. malign
34. traduce
35. vilify
36. disparage
37. denigrate
39. slur
41. dis
42. trash
43. derogate