[Meaning] one who is opposed in any situation, but in a special sense applying to a [sc. legal] judgment, like a)nti/dikos ["opposing party"]; but properly e)nsta/ths is said [of] the person who stands against somebody on the road, as if one should say that Oedipus had become an adversary of Laios.[1]
And Aelian in On divine activities says: "in accordance with a certain oracular response, [he was] wanting to propitiate the divinity which had become an adversary to his household."[2] And elsewhere: "[he] was a most bitter adversary to them."[3]