Paiman
It means covenant or promise, directly relating to the Quranic concept of the primordial covenant (mithaq) between Allah and humanity.
It is Persian in linguistic origin, though the concept is deeply Islamic and found in Arabic as 'Ahd' or 'Mithaq'.
Naturally as Pai-man (パイマン), which follows standard Japanese phonetic patterns perfectly.
While the specific Persian form is not in Hadith, the root concept of keeping promises (wa'd) is emphasized in numerous Hadith as a sign of faith.
It is less common than Arabic equivalents, preserving its uniqueness while remaining culturally authentic to Persian-speaking Muslim traditions.