Enmity (or enmities, plural) is “a feeling or condition of hostility; hatred; ill will; animosity; antagonism”.
Merriam-Webster picked it for today’s word-of-the-day podcast, and in it they discuss the meanings of several of its synonyms:
"Enmity" and its synonyms "hostility," "animosity," and "animus" all indicate deep-seated dislike or ill will. "Enmity" (which derives from an Anglo-French word meaning "enemy") suggests true hatred, either overt or concealed. "Hostility" implies strong, open enmity that shows itself in attacks or aggression. "Animosity" carries the sense of anger, vindictiveness, and sometimes the desire to destroy what one hates. "Animus" is generally less violent than "animosity," but definitely conveys active prejudice or ill will.
A similar word I learned not too long ago is odious, which means “hateful”. It also originates from French, but while enmity comes from the word for enemy, odious comes from the word for “intense hatred”.