Abarim Publications' online Biblical Greek Dictionary
The adverb or preposition εμπροσθεν (emprosthen) describes a going or coming before or in front (of). It consists of (1) the familiar preposition εν (en), meaning in, at, on, (2) the equally familiar preposition προς (pros), which describes a motion toward, and (3) the common suffix of origin -θεν (-then), meaning from.
Our adverb εμπροσθεν (emprosthen) naturally leads to a genitive case and is commonly deployed with verbs of motion, to describe a spatial going/being/passing "in front of", or a temporal going on/happening "before". Often our adverb describes a being "before" someone in the sense of having that person's direct attention (pearls before swine - Matthew 7:6; an ordinance in the eyes of the Father - Matthew 11:26).
Our adverb occurs 48 times in the New Testament; see full concordance.