antagonism
Meaning: hostility
Usage: Superman and Bizarro Superman shared a mutual antagonism, and often fought.
enmity
Meaning: ill will, hatred, hostility
Usage: Mark and Andy have clearly not forgiven each other, because the enmity between them is obvious to anyone in their presence.
inimical
Meaning: hostile, enemylike
Usage: I don’t see how I could ever work for a company that was so cold and inimical to me during my interviews.
malevolent
Meaning: wanting harm to befall others
Usage: The malevolent old man sat in the park all day, tripping unsuspecting passersby with his cane.