The term Vong was the widely used short-hand name for the Yuuzhan Vong species by the populace of the New Republic. However, in Yuuzhan Vong culture, "Vong" was considered an insult as it meant that one was unacceptable to the gods or one's own family.
The term was used by Anakin Solo when speaking to Vua Rapuung on Yavin 4, unaware of the term's unique meaning. Vua explained the meaning of the term to Anakin and urged him to never use the word again due to the severity of the insult.