saai1 dang1 maai6 jau4嘥燈賣油嘥灯卖油

Jyutpingsaai1 dang1 maai6 jau4

Yalesāai dāng maaih yàuh

Definition

To waste one's energy or work hard for nothing.

colloquialdaily actionsother

How it's used

This idiom vividly captures the frustration of expending resources or energy on a task that yields no result. It relies on the imagery of burning oil for light while selling the oil itself, creating a paradox where the act of working consumes the very profit one hopes to gain. It is often used to express regret or to warn someone that their current strategy is futile.

Examples

nei5你gam3咁joeng2樣zou6做zan1真hai6係saai1嘥dang1燈maai6賣jau4油。

Doing it that way is really just a waste of effort.

ngo5我zou6做zo2咗seng4成maan5晚dou1都hai6係saai1嘥dang1燈maai6賣jau4油ze1啫。

I worked all night but it was all for nothing.

Common phrases

zan1真hai6係saai1嘥dang1燈maai6賣jau4油

really a total waste of effort

jyun4完cyun4全saai1嘥dang1燈maai6賣jau4油

completely futile

Common mistake

Do not confuse this with simply wasting time, as it specifically implies that the effort expended is counterproductive or inherently futile. It is a colorful, idiomatic expression that is best reserved for informal settings rather than professional or academic writing.