Latin words meaning ruthless are:
"Perseverantia."
inexorable
I couldn't find "unstoppable" in the latin dictionary but i found the latin word for unconquerable, Inexpugnabilis.
It mean "Unstoppable" in Latin
Relentless
unstoppable
There are total of 11 letters in this word.
unstoppable possible
Continuous, never-ending, forever, or unstoppable.
The Brazen bull was unstoppable
for scrabble points
Unstoppable tennis champion
Cujo is an Indian word meaning "Unstoppable Force".
unstoppable = unaufhaltsam unstoppable = unhaltbar (sports)