Means "son of an adder snake" from the Bosnian word guja
meaning "adder snake".
KASUN Croatian, Serbian, Bosnian
Derived from the Old Slavic term kazac
"to order, command", here referring to one who bore an air of authority, and whose word was heeded and obeyed.
From Bosnian terzija
meaning "tailor", ultimately of Persian origin.