IPA: /ˈbiːtəbl/
KK: /ˈbitəbl/
Able to be defeated or overcome in a competition or challenge.
The team was confident that they were beatable in the upcoming match.
Beatable is formed from "beat" (from Old English "beatan", meaning to strike or hit) and "-able" (meaning capable of). The word "beatable" means capable of being beaten or defeated.
Think of the word 'beat' which means to strike, and remember that 'beatable' refers to something that can be struck down or defeated.