This phrase is not slang, but a traditional Spanish saying. It translates to 'tell me what you show off, and I'll tell you what you lack.' It means that people often boast about the qualities they actually lack.
Examples
- Spanish: Siempre habla de su honestidad, pero nunca devuelve el cambio incorrecto. Como dice el dicho, 'Dime de qué haces gala y te diré de lo que adoleces'.
- English: He always talks about his honesty, but he never gives back the incorrect change. As the saying goes, 'tell me what you show off, and I'll tell you what you lack.'