The Collaborative International Dictionary of English v.0.48:

Absenteeism \Ab`sen*tee"ism\, n.
   The state or practice of an absentee; esp. the practice of
   absenting one's self from the country or district where one's
   estate is situated.
   [1913 Webster]

WordNet (r) 3.0 (2006):

absenteeism
    n 1: habitual absence from work