A deviant; a person who is hostile or destructive to society.
"The jury found him to be a malignant influence in his community due to his history of violent crimes and hostility toward neighbors."
In plain English: A malignant tumor is cancer that grows fast and can spread to other parts of your body if not treated.
"The doctor warned that any malignant growth in his lung needed immediate removal."
dangerous to health; characterized by progressive and uncontrolled growth (especially of a tumor)
"The doctor confirmed that the lump on her breast was malignant cancer cells spreading rapidly through her body."
Harmful, malevolent, injurious.
"The malicious rumor spread quickly and proved to be a malignant force that tore the community apart."
In plain English: Malignant means something that is very harmful and likely to make things much worse, especially when talking about serious diseases like cancer.
"The doctor explained that the tumor was malignant and needed to be removed immediately."
Usage: Malignant is typically reserved for medical contexts describing cancerous growths or serious diseases rather than general moral evil. Avoid using it as a direct synonym for "bad" when referring to non-medical situations; instead, opt for words like malicious or harmful.
The word entered English via Middle French and ultimately traces back to the Late Latin malignans. Originally meaning "ill-willed," it evolved to describe a disease or condition that is likely to cause serious harm or death.