IPA: /məˈlɪɡnəntli/
KK: /məˈlɪɡnəntli/
In a way that is harmful or evil, often causing injury or suffering.
The disease spread malignantly, affecting many people in the community.
Malignantly → It is formed from "malign" (from Latin "malignus", meaning evil or harmful) and "-ly" (meaning in a manner of). The word "malignantly" describes an action done in an evil or harmful manner.
Think of the word 'malign' which means to do harm or evil, and remember that 'malignantly' describes doing something in a harmful way.