(of a person) not able or willing to show feelings or take part (because nervous, arrogant etc)

remote

(of a person) taking pleasure in causing pain to, watching the suffering of, others

vicious, pitiless; causing pain

stubborn

pig-headed, stubborn

(of a person, behaviour, act) showing no pity, sympathy or mercy

mean, heartless

not anxious (about); not (emotionally) concerned (with)

carefree; apathetic

having, showing, no interest; having no personal concern in something

oblivious to

not showing kindness

not nice