WordNet (r) 3.0 (2006):

overplay
    v 1: exaggerate one's acting [syn: overact, ham it up,
         ham, overplay] [ant: underact, underplay]

Moby Thesaurus II by Grady Ward, 1.0:

67 Moby Thesaurus words for "overplay":
   accent, accentuate, carry too far, dramatize, exaggerate, exhaust,
   go overboard, go to extremes, go too far, hyperbolize,
   know no bounds, magnify, maximize, outclass, outdo, outgo, outjump,
   outleap, outmaneuver, outmarch, outpace, outperform, outplay,
   outpoint, outrange, outreach, outride, outrival, outrun, outshine,
   outstep, outstrip, outvie, outwit, overact, overcarry, overdevelop,
   overdo, overdraw, overdrive, overelaborate, overemphasize,
   overexercise, overexert, overexpend, overindulge, overjump,
   overlabor, overleap, overmatch, overreact, override, overspend,
   overstate, overstrain, overstress, overstudy, overtask, overtax,
   overtrain, overuse, overvalue, overwork, pass all bounds, point up,
   protest too much, stretch