Kacper

I assumed this was pronounced Casper. Curious where the 't' sound comes from.

I grew up and still live in Poland, so this name is not unusual to me, but I do understand how it would be unusual to foreigners.

Great name, but weird outside Poland.

What does a cat say when it's throwing-up a furball? "Cack purr"! Seriously though -- it may be kats-per in Poland but in the US, people might be inclined to read it as cack-per which is incredibly ugly to my sensibilities. If you want the originally intended pronunciation and you're an anglophone, why wouldn't you go with a more English phonetic spelling like, Katsper or Katzpar? I'd avoid any spelling that started with "C" as it could end-up looking like, "catsup"! Yikes!

I think this is an uncommon name but it is awesome! I wouldn't exactly name my child this but it's still a great name!