The antonyms of "buys" and "sell" are respectively "sells" and "buy". These words denote the exchange of goods and services for money or other forms of consideration, but in opposite directions. When a person buys something, they typically pay for it with currency or other means of exchange, while when they sell it, they receive a payment for it. Antonyms are useful for creating contrast and diversity in writing or speech, and can help to convey different shades of meaning. By using antonyms, one can more effectively communicate the nuances of language and convey their intended message to the audience.