The Collaborative International Dictionary of English v.0.48:

goof-off \goof-off\ n.
   A person who habitually shirks his duties or avoids work; an
   idle worthless person. [Informal]

   Syn: goldbrick, ne'er-do-well, good-for-nothing,
        good-for-naught.
        [WordNet 1.5 + PJC]

WordNet (r) 3.0 (2006):

goof-off
    n 1: an idle worthless person [syn: goldbrick, goof-off, ne
         'er-do-well, good-for-nothing, no-account, good-for-
         naught]