An Etymological Dictionary of the German Language/Annotated/Gewissen

by Friedrich Kluge

Gewissen, neuter,‘conscience,’ from Middle High German gewiȥȥen, feminine neuter, ‘knowledge, information, privity, inner consciousness, conscience,’ even in Old High German giwiȥȥanî, feminine, ‘conscience’ (Dutch geweten); probably an imitation of Latin conscientia (German ge equivalent to Latin con, as in Gevatter), compare also barmherzig; in Gothic midwissei. Old High German giwiȥȥanî is most closely connected with wissen, THG. infin wiȥȥan.