repay

Compared meaning: to give money or something back (verb).

比较义项：把钱或物归还给原来拥有它的人（动词）。

• return

  General word for giving something back to whoever had it before; not limited to money, and works for objects, favors, or loans alike.

  泛指把东西归还给原本拥有它的人，不限于金钱，也可用于物品或恩惠。

  Please return my umbrella when you're done with it.

  你用完之后请把我的雨伞还给我。

• repay 本词

  Specifically about paying back money that was borrowed or owed, often implying a debt or obligation; can also mean repaying a favor.

  专指偿还所借或所欠的钱款，带有债务或义务的意味，也可用于报答恩情。

  I promise to repay the money you lent me last month.

  我保证会把你上个月借给我的钱还给你。

• refund

  Specifically used when a seller or business gives back money a customer has already paid, usually for returned or unsatisfactory goods.

  专指商家或卖方把顾客已支付的钱退还回去，通常用于退货或对商品不满意的情况。

  The store gave me a refund because the shoes were too small.

  因为鞋子太小，商店给我退了款。

All three words mean to give something back. Return is the most general word, for any object, money, or favor. Repay specifically means paying back borrowed money, or repaying a favor. Refund specifically means a seller gives back money a customer already paid.

这三个词都含“归还”之意，但对象和场合不同：return最通用，可指归还任何物品或钱款；repay专指偿还欠款，也可表示报答恩情；refund专指商家把顾客已付的货款退还。这里不比较repay的“报复”义项。

Compared meaning: to give something back for good behavior (verb).

比较义项：因对方的好行为或所做的事而给予回报（动词）。

• reward

  Reward means giving something — praise, money, or a gift — to someone for good behavior or work, usually from an authority recognizing merit, not for repaying a specific debt.

  reward表示因对方的好行为或工作而给予某人东西——表扬、金钱或礼物——通常由权威一方给予以表彰功劳，而不是偿还具体的欠债。

  The teacher rewarded the whole class with extra recess for good behavior.

  老师奖励全班额外的课间休息时间，因为他们表现良好。

• repay 本词

  Repay means to give back money, a favor, or kindness to the specific person who gave it, settling a debt or obligation you owe them directly.

  repay表示把金钱、恩惠或善意归还给当初给予自己的那个人，直接偿还欠对方的具体债务或人情。

  I finally saved enough money to repay the loan my brother gave me.

  我终于攒够钱偿还了哥哥借给我的贷款。

Both words mean giving something back for good behavior. Reward means giving praise, money, or a gift for good work, usually from someone in authority. Repay means giving back money or kindness to the exact person who gave it, settling a debt.

这两个词都表示因对方做了好事而有所回报，但reward更强调认可或表彰对方的良好表现或功劳，常由老师、雇主等权威一方给予，不一定是偿还具体的欠债；repay更强调把对方给予自己的具体恩惠或金钱直接归还给那个人，带有偿还欠债或人情的意味。