rival

Compared meaning: a person or group competing against another (noun).

比较义项：竞争对手（统称或个体）（名词）。

• competition

  Competition is uncountable and collective here — it means all of one's rivals together (as in 'the competition'), never a single rival, and is not used with 'a'.

  在这个义项中，competition 是不可数的集合名词，指所有竞争对手的整体（如“the competition”），而不是某一个具体的对手，也不能加“a”使用。

  Our new pricing strategy left the competition scrambling to keep up.

  我们新的定价策略让所有竞争对手都手忙脚乱，难以跟上。

• competitor

  Competitor is a countable noun for one specific company or person that competes against you — the word to use when naming a single rival, unlike the collective 'competition'.

  competitor 是可数名词，指某一个具体的、与你竞争的公司或个人；要指某一个具体的对手时应该用这个词，而不是表示整体的 competition。

  A new competitor entered the market last month with lower prices.

  上个月有一个新的竞争者以更低的价格进入了市场。

• rival 本词

  Rival stresses an ongoing, often personal or historic opposition, and is commonly used for sports teams, classmates, or businesses long known for competing with each other.

  rival 强调一种持续存在、常带有个人色彩或历史渊源的对抗关系，常用来形容体育队伍、同学，或长期彼此竞争的企业。

  The two schools have been fierce rivals in basketball for decades.

  这两所学校在篮球方面几十年来一直是激烈的竞争对手。

• contender

  Contender highlights someone actively competing for a specific prize, title, or position, especially when they have a genuine chance of winning, common in contests, sports, and elections.

  contender 突出的是某人正在争夺某个具体的奖项、头衔或职位，尤其是指真正有获胜机会的参与者，常用于比赛、体育和选举等场合。

  With three strong performances, she became a serious contender for the championship.

  凭借三次出色的表现，她成为了争夺冠军的有力竞争者。

Competition, competitor, rival, and contender can all mean someone competing against you, but their use differs. Competition is uncountable, meaning all rivals. Competitor is countable, one specific rival. Rival stresses long, personal opposition, as in sports. Contender means someone with a real chance of winning.

这几个词都可以表示“竞争对手”，但用法不同：competition 是不可数的集合名词，指所有竞争对手的整体（如“the competition”），不能用来指某一个具体对手；competitor 是可数名词，指某一个具体的竞争对手（人或公司）；rival 强调长期或带有个人色彩的对抗关系，常用于运动队、同学或长期竞争的企业；contender 特指在某项比赛、头衔或职位的争夺中有真正获胜机会的参与者。这里不比较 competition 表示“比赛项目”（如 singing competition）的义项。