«مَا يْفَرْقَعْشِ الَّا الصَّفِيحِ الْفَاضِي»

The saying rests on a simple physical observation: tap a hollow vessel made of thin sheet metal and it rings, while a full one gives back only a dull thud. The verb here means that hollow ringing, not a bang or explosion.

Applied to people, it suggests that those who boast and make loud claims usually lack the qualities they advertise, while genuine substance tends to stay quiet.

Used to dismiss someone who brags loudly or makes grand claims, implying their noise reveals a lack of real merit. It carries mild scorn and is a pointed personal criticism, so aiming it directly at someone can come across as insulting.