An Etymological Dictionary of the German Language/echt
echt, adj., ‘genuine, real, legitimate,’ simply ModHG. adopted from MidG. and LG., where echt is the normal corresponding of MidHG. and OHG. êhaft, ‘lawful’; comp. Du. echt; akin to OFris. âft, ‘lawful’; from Ehe, compared with which the adj. has retained the old meaning of Ehe, ‘law.’ By means of the law-books based on the Saxon Code the LG. adj. found its way into HG. but not until after Luther; yet the word does not occur in the UpG. dialects.