A powerful blow can be described using different words, depending on the situation. One synonym for "powerful blow" is a "forceful punch," which denotes a sudden, intense impact that delivers great force. Another word for a powerful blow is a "devastating strike," which suggests a devastating effect on the victim, not just physically but also emotionally. Similarly, a "heavy blow" refers to a forceful impact that carries weight and can leave the victim reeling. Finally, a "mighty blow" suggests a level of strength and power that is almost superhuman, indicating an attack that is difficult to fend off. Overall, there are many ways to describe a powerful blow to convey its impact and significance.