赚 (zhuàn) 'to earn' is a phono-semantic compound. The shell radical 贝 (bèi) on the left marks it as a money word, since cowrie shells once served as currency, while 兼 (jiān) on the right supplies the sound. The character means to make a profit or earn money. The traditional form is 賺.

Origin

phono-semantic compound

Root

贝 (shell/money, semantic) + 兼 (jiān, phonetic)