The adjective is derived from forth + coming; or from Middle English forth commyng, *forthcominge, present participle of forth-comen, from Old English forþcuman, forþ-cuman (present participle *forþcumende), from forþ- (ultimately from Proto-Indo-European *per-) + cuman (ultimately from Proto-Indo-European *gʷem-). Compare Dutch voortkomend, German fortkommend.