IPA: /ˈvɪlənəsli/
KK: /ˈvɪlənəsli/
In a way that shows evil or wicked behavior, like a villain.
The character in the movie acted villainously, plotting against the hero.
Villainously → It is formed from "villain" (from Old French *vilain*, meaning a farmhand or peasant, later evolving to mean a wicked person) and the suffix "-ously" (meaning in a manner of). The word "villainously" means in a wicked or immoral manner, reflecting the negative qualities associated with a villain.
Think of a 'villain' as someone who acts in a 'wicked manner' ('-ously') — that's why 'villainously' describes actions that are morally wrong.