To pay someone less than their work is worth, or less than they should have been given. It works in two rather different situations, and it is worth separating them.

To pay someone less than their work is worth付給某人比他工作的價值還少的錢 or less than they should have been given或是比他們應得的還少 It works in two rather different situations這個字用在兩種相當不同的情況 and it is worth separating them值得把它們分開來看

The first is about fairness over time: a company underpays its cleaners — the wage is legal, the money arrives, but it is too little for the work. This is the sense you meet in news and in arguments about wages, and it carries clear criticism of the employer.

The first is about fairness over time第一種是關於長期下來的公平性 a company underpays its cleaners像一家公司underpays its cleaners（給清潔工的薪水過低） the wage is legal, the money arrives薪水是合法的、錢也有發 but it is too little for the work但相對於做的工作來說太少了 This is the sense you meet in news and in arguments about wages這是你在新聞和薪資爭議裡會遇到的用法 and it carries clear criticism of the employer而且帶著對雇主明確的批評

The second is about a specific mistake or shortfall: the office underpaid me last month, they underpaid the invoice by three hundred dollars. Here nothing is being judged unfair — someone simply paid less than the agreed amount, and it can be fixed.

The second is about a specific mistake or shortfall第二種是關於一次具體的錯誤或短付 the office underpaid me last month像辦公室上個月underpaid me（少付我薪水） they underpaid the invoice by three hundred dollars或他們少付了這張發票三百元 Here nothing is being judged unfair這裡並沒有在評斷誰不公平 someone simply paid less than the agreed amount只是某人付的錢比約定的少 and it can be fixed而且是可以修正的

English uses the same verb for both, and the context decides.

English uses the same verb for both英文對這兩種情況用同一個動詞 and the context decides靠上下文來判斷是哪一種

The forms are irregular because 'pay' is: underpay, underpaid, underpaid — never 'underpayed'. It is usually transitive (you underpay SOMEONE, or underpay AN AMOUNT), and it appears very often in the passive: workers are being underpaid, I was underpaid.

The forms are irregular because 'pay' is這個字的變化是不規則的，因為'pay'本身就是 underpay, underpaid, underpaid像underpay、underpaid、underpaid never 'underpayed'絕對不是'underpayed' It is usually transitive這個字通常是及物動詞 (you underpay SOMEONE, or underpay AN AMOUNT)（你underpay某人，或underpay某個金額） and it appears very often in the passive而且很常用被動式 workers are being underpaid, I was underpaid像workers are being underpaid、I was underpaid

In fact the passive and the adjective 'underpaid' are far more common than the active verb; you will read 'staff are underpaid' ten times for every 'the company underpays staff'. The related noun is 'underpayment', mostly used for the accounting kind.

In fact事實上 the passive and the adjective 'underpaid'被動式和形容詞'underpaid' are far more common than the active verb都比主動的動詞形式常見得多 you will read 'staff are underpaid' ten times for every 'the company underpays staff'你會看到十次'staff are underpaid'，才看到一次'the company underpays staff' The related noun is 'underpayment'相關的名詞是'underpayment' mostly used for the accounting kind主要用在會計上的那種意思