WordNet (r) 3.0 (2006):

overspend
    v 1: spend more than available of (a budget) [ant: underspend]
    2: spend at a high rate [ant: underspend]

Moby Thesaurus II by Grady Ward, 1.0:

38 Moby Thesaurus words for "overspend":
   be had, carry too far, exaggerate, exhaust, go overboard,
   go to extremes, go too far, know no bounds, overact, overcarry,
   overdevelop, overdo, overdraw, overdrive, overelaborate,
   overemphasize, overexercise, overexert, overexpend, overindulge,
   overlabor, overpay, overplay, overreact, overstrain, overstress,
   overstudy, overtask, overtax, overtrain, overuse, overwork,
   pass all bounds, pay, pay dearly, pay exorbitantly, pay too much,
   protest too much