Quiz: Remember the definition of mal de mer?
1540s, laysy, of unknown origin. Replaced native slack, slothful, and idle as the main word expressing the notion of "averse to work." In 19c. thought to be from lay (v.) as tipsy from tip. Skeat is responsible for the prevailing modern view that it probably comes from Low German, cf. Middle Low German laisch "weak, feeble, tired," modern Low German läösig, early modern Dutch leuzig, all of which may go back to the PIE root *(s)leg- "slack." According to Weekley, the -z- sound disqualifies a connection with French lassé "tired" or German lassig "lazy, weary, tired." A supposed dialectal meaning "naught, bad," if it is the original sense, may tie the word to Old Norse lasenn "dilapidated," lasmøyrr "decrepit, fragile," root of Icelandic las-furða "ailing," las-leiki "ailment." Lazy Susan is from 1917.