1. mischievous
a mischievous grin/smile/look
That boy isn't as mischievous as we thought he would be.
He likes to be mischievous.
Keep an eye on the boys. They're mischievous.
mischievous child
He looked at me with a mischievous twinkle in his eyes
It is true the boy is mischievous, but he is kind at heart.
I’m twenty-seven.” The women got up and left, and Dykstra smiled, mischievous.
She looked young, and mischievous, without a care in the world
The Joker character in "Batman" is known for being mischievous and cunning, and always has a thing or two up his sleeve.
The beginning of the words of his mouth is foolishness; and the end of his talk is mischievous madness.
I think these rumours are mischievous.
He was a mischievous child, always getting into trouble.
He is so mischievous, he takes pleasure in playing nasty tricks on people.
He was as mischievous as any boy in the class.
2. vicious
a vicious thug
You have to be careful ’cos they can get quite vicious if they’re frightened or scared or something.
Loose laces caught in vicious vacuums?
Every soul on earth, virtuous or vicious, shall perish!
I know you're upset with her, but there's no need to be vicious
She's so vicious. I don't like her.
vicious attack/ campaign/rumour
The police said that this was one of the most vicious attacks they'd ever seen.
The definition of vicious is someone or something that is especially cruel, harsh or violent, especially when the unkindness is done intentionally.
These vicious rumours aren't true!/Their vicious children do what they want!
vicious - extremely violent
Judge Isaac Parker characterised Cherokee Bill as the most vicious of all the outlaws in the Oklahoma Territory, who killed for the love of killing.
“You’re vicious."
An example of vicious is when you cruelly attack someone's looks and character for no reason.
In most cases, people, even the most vicious, are much more naive and simple-minded than we assume them to be. And this is true of ourselves too.