shammer

from WordNet (r) 3.0 (2006)

shammer
    n 1: someone shirking their duty by feigning illness or
         incapacity [syn: {malingerer}, {skulker}, {shammer}]
    2: a person who makes deceitful pretenses [syn: {imposter},
       {impostor}, {pretender}, {fake}, {faker}, {fraud}, {sham},
       {shammer}, {pseudo}, {pseud}, {role player}]

from The Collaborative International Dictionary of English v.0.48

Shammer \Sham"mer\, n.
   One who shams; an impostor. --Johnson.
   [1913 Webster]