Nefarious
extremly wicked (adj.)
Synonims:
Horrible,evil,rotten,mean,abominable,criminal
Antonyms:
good, honorable, respectable, virtuous, worthy
Sentences:
The girls was very nefarious by not giving the boy's phone back.
How nefarious of you to borrow that without my concern.
Stealing Peoples Stuff Prank!