炒股 (chǎo gǔ): 株を投機する

He started speculating in stocks last year, staring at the market every day, and doesn't even have time to eat.

Don't put all your savings into stock speculation. If you lose money, you won't even be able to pay your child's tuition.

She made some money from stock speculation, but she says she'll never do it again because it affects her sleep too much.

Many people think stock speculation can make them rich quickly, but in the end they lose all their capital.

He speculates in stocks while working, secretly checking the market during work hours, and almost got caught by his boss.