Definition from Wiktionary, the free dictionary
- Unable to be stopped.
- King Hrothgar thought that Grendel was unstoppable.
2011 October 20, Jamie Lillywhite, “Tottenham 1 - 0 Rubin Kazan”, BBC Sport:
- However Russian Pavlyuchenko stunned his compatriots with an unstoppable 25-yard drive into the top corner.
unable to be stopped