schlicht.

Chiefly Low German, also to a lesser degree Central German variant of schlecht. From Middle Low German slicht and northern Middle High German sliht (both “flat, straight, simple”), from Proto-Germanic *slihtaz, which see for cognates. Since the Late Middle Ages, schlecht/schlicht developed the sense “bad”, which became predominant over time, but did not displace the original one entirely. By the 17th century, attempts were made to reserve the i-variant specifically to the older meaning, but the semantic split between both forms was completed only during the 19th century. The adverbs schlechthin and schlechterdings (both “plainly, absolutely”) remain as relicts to this day.