Definition of cruel adjective from the Oxford Advanced Learner's Dictionary

Oxford3000

cruel

adjective
ˈkruːəl
 
; ˈkruːəl
 
crueller, cruellest
 
1 cruel (to somebody/something) having a desire to cause pain and sufferinga cruel dictatorI can't stand people who are cruel to animals.Her eyes were cruel and hard.Sometimes you have to be cruel to be kind(= make somebody suffer because it will be good for them later).
Opposite
kind
2 causing pain or sufferinga cruel punishment/jokeHer father's death was a cruel blow.cruelly
ˈkruːəli
 
; ˈkruːəli
 
adverbThe dog had been cruelly treated.I was cruelly deceived.