Where does “Pacastáin” come from?

Pacastáin (Irish) comes from Urdu پاکستان, from Classical Persian پَاک.

Ancestry of “Pacastáin”, step by step

StepLanguageWordMeaning
1UrduپاکستانLand of the Pure
2Classical Persianپَاک—
Every word from Classical Persian پَاک →Every word from Urdu پاکستان →