Dep:
1.to set oneself against, oppose, withstand, τινι Hdt., Thuc., etc.; οὐκ ἐναντιώσομαι τὸ μὴ οὐ γεγωνεῖν I will not refuse to speak, Aesch.; τοῦτό μοι ἐναντιοῦται πράττειν this prevents me from doing, Plat.
2.to contradict, gainsay, Eur., Thuc., etc.
3.of the wind, to be adverse, Soph., Thuc.