。
She is hostile toward me.
Literal
She [topic-は] me [toward-に対し] hostile is.
に対し is the conjunctive (連用形) form of に対して — same meaning, more compressed and slightly more formal. You'll see に対し in news headlines and formal writing where に対して would feel a beat too long. 敵対的 is a na-adjective formed by attaching the suffix ~的 ('-like, -ic') to 敵対 ('opposition, hostility'); the ~的 suffix is hugely productive in modern Japanese for making nouns into adjectives — 個人的 ('personal'), 客観的 ('objective'), 経済的 ('economic'). Many of these are loan-translations from Western academic vocabulary that entered Japanese in the Meiji era.