An Etymological Dictionary of the German Language/Annotated/Laster

by Friedrich Kluge

Laster, neuter, ‘vice, crime,’ from Middle High German and Middle Low German laster, neuter, ‘abuse, disgrace, mistake,’ Old High German lastar, neuter. It is connected with a strong verb lahan (for the loss of h before s compare Mist) preserved in Old High German, equivalent to Anglo-Saxon leán, ‘to blame.’ Pre-Teutonic lahstra- is formed from the verbal stem lah with the suffix stra-, which represents the earlier form tra seen in Anglo-Saxon leahtor, neuter, ‘reproach, sin’ (obsolete in English). Another derivative from the same stem is seen in Scandinavian lǫstr (Gothic *lahstus), Middle English last, ‘mistake, defect.’ In the non-Teutonic languages the word may be compared with Old Irish locht (from lokto-), ‘mistake.’