What is the German equivalent of English word paint ball?

There isn't a single perfect equivalent for "paintball" in German, as it's a relatively recent sport. However, the most common and easily understood translation would be Paintball. It's often used as is, similar to how English borrows words from other languages.

You might also see descriptive phrases like Farbkugelspiel (literally "color ball game") or Gelballerspiel (gel ball game, if using gel-based paintballs), but these are less common and somewhat cumbersome. Simply using Paintball is the most practical and widely understood option.