unvanquishable

Unvanquishable describes something or someone that cannot be defeated, conquered, or overcome.

It intensifies the already strong vanquish by adding the prefix un- and suffix -able, emphasizing absolute resistance to subjugation.

The word appears most often in literary or heroic contexts: an unvanquishable spirit, unvanquishable courage in the face of tyranny.

While invincible is more common in everyday speech, unvanquishable carries a more dramatic, often archaic tone.