«اِلْفَاجِرْ يَاكُلْ مَالِ التَّاجِرْ»

The saying observes that whoever is shameless and strong enough to lay hands on other people's property usually ends up consuming it; 'eating' wealth is the ordinary Arabic idiom for appropriating it. The brazen one is the bold, capable grabber rather than simply a dissolute person, and nerve, not rightful claim, settles who prospers.

The merchant appears mainly because his title rhymes with the word for the brazen one, not because traders are singled out. The real target is anyone whose wealth lies exposed to a daring, able exploiter, making the line a general comment on predatory audacity.

Fits a wry or bitter remark when a bold, unscrupulous person has profited from someone else's money, or as a caution to protect one's means from such people. Avoid presenting it as a claim that merchants specifically are the usual victims.