This word means whore or fuck.
He uses this word the most, since it's from his language
They use a variation of the world known as "Kurva". You don't see it a lot because neither of them appear in a lot of comics.
Perhaps the most infamous, Croatia hates kebab not because he wants to follow brother Serbiaball, but the Arabs call him "Kurwa-tia". He gets quite agitated when called so.
He uses a variation of the word known as "curvă" (IPA: /kurvə/), which also means whore.
Coincidentally, Taiwanball's traditional language, Taiwanese, has a swear word that sounds similar to "Kurwa", which is "靠夭" . The literal translation is "You're crying because you're hungry". Weird.
He uses a variation of the word known as "Shiba", as this word means "f*ck".
Surprisingly, the US hasn't censored this word as much on TV.