敵(かたき)rival, opponent, adversary, competitor, enemy (esp. one with which there is longstanding enmity), foe, revenge, spouse

僕(ぼく)は恋(こい)敵(がたき)に意中(いちゅう)の子(こ)を取(と)られてしまった。

I ended up losing the girl I had my eyes on to my love rival. {rival, opponent, adversary, competitor, enemy (esp. one with which there is longstanding enmity), foe, revenge, spouse}

父(ちち)の敵(かたき)を討(う)つために復讐(ふくしゅう)を計画(けいかく)しています。

I am planning revenge to defeat my father's enemy. {rival, opponent, adversary, competitor, enemy (esp. one with which there is longstanding enmity), foe, revenge, spouse}

商売(しょうばい)上(じょう)の敵(かたき)に勝(か)つために商品(しょうひん)の値下(ねさ)げをしました。

In order to beat my business rival, I reduced the price of my products. {rival, opponent, adversary, competitor, enemy (esp. one with which there is longstanding enmity), foe, revenge, spouse}

敵(かたき)を取(と)ってみせるぞとばかりに仲間(なかま)たちは復讐(ふくしゅう)に燃(も)えている。

As if to say they will defeat their enemy, my comrades are burning with revenge. {rival, opponent, adversary, competitor, enemy (esp. one with which there is longstanding enmity), foe, revenge, spouse}

親(おや)の敵(かたき)を討(う)つことが出来(でき)ればこそ、僕(ぼく)は夜(よる)にぐっすり眠(ねむ)ることが出来(でき)るのだ。

Only by avenging my parents' enemy, can I truly sleep soundly at night. {rival, opponent, adversary, competitor, enemy (esp. one with which there is longstanding enmity), foe, revenge, spouse}