«زَيِّ الْخُنْفُسْ لَا يِتَّاكِلْ وَلَا يِتْلِعِبْ فِيهْ»

The saying brands someone or something as completely without value. Just as a beetle, a stock image of something unappealing, is neither food nor a source of amusement, the target is pictured as failing on both fronts: it cannot be put to serious use, and it cannot even offer diversion.

Its force lies in closing off every possible reason to value the person or thing being mocked. Whether one looks for usefulness or enjoyment, the speaker sees neither. It is a sweeping insult, not merely a complaint about one missing skill.

Use it to dismiss someone or something that offers neither practical benefit nor any pleasure, such as a broken object kept around for no reason. Aimed at a person, it is harsh, labeling them worthless in every respect; it is blunt and mocking, suited only to informal talk.