overwork
v.
"to cause to work too hard," 1520s, from over- + work, v.. Old English oferwyrcan meant "to work all over," i.e. "to decorate the whole surface of." Related: Overworked; overworking.
n.
"work beyond a person's strength," 1819; see overwork, v.. Old English oferweorc meant "a superstructure, sarcophagus, tomb."