The Collaborative International Dictionary of English v.0.48:

Hooky \Hook"y\ (h[oo^]k"[y^]), a.
   Full of hooks; pertaining to hooks.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Hooky \Hook"y\ (h[oo^]k"[y^]), n. [Written also hookey.] [Cf.
   Hook, v. t., 3.]
   A word used only in the expression to play hooky, to be
   truant, to run away; -- used mostly of youths absent from
   school without a valid reason and without the knowledge of
   their parents. Also (figuratively and jocosely), to be absent
   from duty for frivolous reasons.
   [Webster 1913 Suppl. +PJC]

         This talk about boys . . . playing ball, and "hooky,"
         and marbles, was all moonshine.          --F. Hopkinson
                                                  Smith.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

hooky
    n 1: failure to attend (especially school) [syn: truancy,
         hooky]

Moby Thesaurus II by Grady Ward, 1.0:

30 Moby Thesaurus words for "hooky":
   AWOL, French leave, abscondence, absence, absence without leave,
   absentation, absenteeism, absenting, cut, day off, default,
   departure, disappearance, escape, excused absence, fleeing,
   furlough, holiday, leave, leave of absence, leaving, nonappearance,
   nonattendance, running away, sabbatical leave, sick leave, truancy,
   truantism, unexcused absence, vacation