‘Làng fèi’ is a verb meaning 'to waste' — typically referring to the unnecessary or careless use of resources such as time, money, food, energy, or materials. The character ‘浪’ (làng) originally means 'wave' but here carries the sense of 'reckless' or 'uncontrolled'; ‘费’ (fèi) means 'expense' or 'effort'. Together, they evoke the idea of squandering something valuable without purpose or benefit. It’s commonly used in daily life when criticizing inefficiency, overconsumption, or poor planning.

This word often appears with objects like 时间 (shíjiān, 'time'), 食物 (shíwù, 'food'), 水 (shuǐ, 'water'), or 金钱 (jīnqián, 'money'). It frequently occurs in warnings, advice, or moral reflections — for example, parents telling children not to waste food, or environmental campaigns urging people not to waste electricity. While neutral in register, it carries a mild negative connotation and implies disapproval or regret.