anti- (ant-)是希腊语源的前缀，它原是个介词，意思相当于against或opposing,即表示“相对”或“相反”。anti-最早出现在直接进人英语的希腊单词中，是一个只能与词根结合的原生词缀。现在，它成了英语中非常活跃的介词性派生前缀， 能与许多名词缀合，构成相应的形容词或名词。原生前缀ant-是anti- 的异体，用在以元音字母及h开头的词根或词干之前。 它只出现在借词之中。

我们先来观察几个anti- (ant-)与词根缀合的例子。 

antibiotic [ anti- = opposing 反；bi =life 生命;-otic a . = having the quality of 有…性能的=> “having the quality of opposing a certain life 能与某种生物作对的”→ ]a. opposing the disease- carrying bacteria 抑制病菌的，抗生的 /Penicillin is an antibiotic substance.盘尼西林是种抗生素。 

antidote [ anti- = against 对抗；dot = given as a remedy 用来做药 的；-e “a remedy against sth.用来对抗某物的药”→]n . medicine that counteracts the effect of a poison 解毒药 / Milk is an antidote for some poisons.牛奶可以解某些毒药。

antipathy [anti- = against 反；pathy = feeling 感情=>“a feeling against sb. or sth.反对某人或某物的感情”→]n . strong dislike 反感，厌恶 / She has a strong antipathy to a snake.她非常讨厌蛇。

antipathetic a. 引起反感的；素来厌恶的