ف ض وf-ḍ-w
(ن) فَضَا يَفْضُوْ فَضَآءًfaḍā yafḍū faḍāʾan (original form: فَضَوَ يَفْضُوُfaḍawa yafḍuwu): for a place to be spacious and empty. (This verb is not used in the Quran.)
Form IV (ifʿāl) اَفْضٰى يُفْضِيْ اِفْضَآءًafḍā yufḍī ifḍāʾan: to reach into open space; with the preposition «اِلٰىilā»: to reach someone without any barrier, metonymically: of husband and wife, to be alone together and have conjugal relations. This root occurs only once in the Quran: ﴿وَقَدْ اَفْضٰى بَعْضُكُمْ اِلٰى بَعْضٍ﴾ (An-Nisāʾ 4:21)