名詞 antagonist:

1. someone who offers opposition
   同義詞：adversary, opponent, opposer, resister
2. a muscle that relaxes while another contracts
3. a drug that neutralizes or counteracts the effects of another drug

1. I am bound to furnish my antagonists with arguments, but not with comprehension.
   我一定要向對手提供爭論點，但并無予以理解的必要。
2. He ripped into his antagonist with fury.
   他向他的對手猛撲過去。
3. A sparrow fluttering about the church is an antagonist which the most profound theologian in Europe is wholly unable to overcome.
   在教堂附近飛來飛去的麻雀，是為歐洲學識最深的神學家們完全無法克服的敵手。

an.tag.o.nist

n.（名詞）
One who opposes and contends against another; an adversary.See Synonyms at opponent
對抗者，對手，敵手：反對另一人及與另一人競爭的人；對手參見 opponent
The principal character in opposition to the protagonist or hero of a narrative or drama.
反面主角：敘事文學或戲劇中與主人公或英雄相對立的主要人物
Physiology A muscle that counteracts the action of another muscle, the agonist.
【生理學】 拮抗肌，對抗?。旱窒∪庾饔玫牧硪粔K肌肉，收縮肌
Biochemistry A chemical substance that interferes with the physiological action of another, especially by combining with and blocking its nerve receptor.
【生物化學】 拮抗藥，對抗藥：通過與另一種化學物質的結合或阻礙其神經接受體而干擾其生理作用的一種化學物質

【引伸】
antag.onis.tic
adj.（形容詞）
antag.onis.tically
adv.（副詞）