1
: very violent and cruel
a vicious attack/battle
2
: very dangerous
a vicious dog
3
: having or showing very angry or cruel feelings
vicious gossip
a vicious tone of voice
I know you're upset with her, but there's no need to be vicious.
4
informal
: very bad or severe
a vicious storm
a vicious headache
Cite this Entry
“Vicious.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/vicious. Accessed 14 Apr. 2026.
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