An Etymological Dictionary of the German Language/Annotated/Laffe
Laffe, masculine, ‘puppy, dandy,’ from Middle High German lape, lappe, masculine, ‘simpleton, dandy.’ The relation of Modern High German Lump to Lumpen makes the existence of Middle High German lappe, ‘dandy,’ as well as *lappe, ‘rags,’ conceivable; yet the Modern High German form has ff compared with the Middle High German pp; compare läppich. Others refer Laffe to Dutch and Low German laf, ‘stale, insipid.’