The most common Persian word is Masīhī (مسیحی), from Arabic.,Other words are Nasrānī (نصرانی), from Syriac for "Nazarene", and Tarsā (ترسا), from Middle Persian word Tarsāg, also meaning "Christian", derived from tars, meaning "fear, respect".
Is there an answer to this question (If it cannot be answered, say "unanswerable"): What does tars mean?
fear, respect