antagonist [ ant- ( anti-) = against 对抗；agon = to contest 竞争；-ist n.= person 人→]n . person who contests or fights against another 对抗者，敌手 / The knight defeated each antagonist who came against him.骑士把跟他对抗的人一一打败了。 antagonism n. 对抗；对抗性 

antagonistic a. 对抗的；有反作用的 

antonym [ ant- (anti-) = opposite 相反；onym = mame 名称=>“an opposite name 相反的名称”→]n . word that means the opposite of another word 反义词 / “Hot” is the antonym of“cold”, hot是cold的反义词。

antonymous a .反义词的

anthelminthic [ ant- ( anti-) = opposing 抗；helminth=worm 虫；-ic a . =having the quality of 有…性能的“opposing worms 能对付虫的”→]a . destroying or expelling intestinal worms 驱除肠内寄生虫的 / That is an anthelminthic remedy for oxen.这是一种给牛吃的驱虫剂。

下面是anti-作为派生前缀构词的几个例子： 

antiaircraft [ anti- = against 防；aircraft n .飞机→]a . used against enemy aircraft 防空袭的 / Please come into the antiaircraft dugout.请进入防空壕。