It is actually much simplier than that. The word you're speaking of is "Farangi" which is Farsi for foreigner.
Farsi is an indo-european language so beside loan words which infiltrated the language during Reza Shah's moderinization of Iran, many of them actually share the same root as other Indo-European languages like English, French or German.
Farangi is one of those words. It is not a borrowed word