From paga'; an object of attack -- mark.
see HEBREW paga'
H4645. miphga
מִפְגָּע noun [masculine] thing hit, mark; — לְמ ׳שַׂמְתַּנִי לָ֑ךְ לָ֫מָה Job 7:20 (compare also מָּגַע Hiph`il 1.).