malign

adj. evil, harmful

v. slander, make evil and untrue statements about another; speak in a wicked manner of

Malignant (from the Latin roots mal- = "bad" and -genus = "born") is a medical term used to describe a severe and progressively worsening disease. The term is most familiar as a description of cancer. A malignant tumor may be contrasted with a non-cancerous benign tumor in that a malignancy is not self-limited in its growth, is capable of invading into adjacent tissues, and may be capable of spreading to distant tissues (metastasizing), while a benign tumor has none of those properties. Uses of "malignant" in oncology:Malignancy, malignant neoplasm, and malignant tumor are synonymous with cancerMalignant ascitesMalignant transformation
See more at Wikipedia.org...

Verb
1. speak unfavorably about; "She badmouthes her husband everywhere"
(synonym) badmouth, traduce, drag through the mud
(hypernym) defame, slander, smirch, asperse, denigrate, calumniate, smear, sully, besmirch
(derivation) smear, vilification, malignment
Adjective
1. evil or harmful in nature or influence; "prompted by malign motives"; "believed in witches and malign spirits"; "gave him a malign look"; "a malign lesion"
(antonym) benign, benignant
(similar) cancerous
(see-also) harmful
(attribute) malignity, malignancy, malignance
2. having or exerting a malignant influence; "malevolent stars"; "a malefic force"
(synonym) malefic, malevolent, evil
(similar) maleficent

(v. i.)
To entertain malice.
  

(a.)
Unfavorable; unpropitious; pernicious; tending to injure; as, a malign aspect of planets.
  

(a.)
To treat with malice; to show hatred toward; to abuse; to wrong; to injure.
  

(a.)
To speak great evil of; to traduce; to defame; to slander; to vilify; to asperse.
  

(a.)
Malignant; as, a malign ulcer.
  

(a.)
Having an evil disposition toward others; harboring violent enmity; malevolent; malicious; spiteful; -- opposed to benign.
  

med. malignant