Unstoppable means impossible to bring to a halt. An unstoppable force, unstoppable momentum, seemed unstoppable.
It is almost always an exaggeration and almost always said before something is stopped. The unstoppable force meeting the immovable object is a standing paradox, and the answer is that both cannot exist in the same universe.
1adjectiveunstoppableImpossible to bring to a halt.
“Once the fire reached the dry forest, it was unstoppable.”
unstoppable is a quality.
From un- + stoppable.
Etymology from Wiktionary, CC BY-SA