Although I'm not sure of a colloquial term (it would be very difficult to find such a thing in script because the Ptolemies would have worked hard to destroy such insults), when Egyptian priests wanted to subtly insult the Ptolemies they tended to write Wn-nfr on the royal cartouche (the royal name) when writing about a Ptolemy king. This was meant to say that the true god of Egypt is Osiris and not any foreign Xerxes or Ptolemy or Alexander, while not actually insulting the king, per-se.

Likely because no Ptolemy knew Egyptian until Kleopatria, they had no idea this was happening and the priests probably didn't let them know. It was too dank a prank.