WordNet (r) 3.0 (2006):

counterproductive
    adj 1: tending to hinder the achievement of a goal

Moby Thesaurus II by Grady Ward, 1.0:

81 Moby Thesaurus words for "counterproductive":
   baleful, baneful, barren, bootless, choking, constrictive,
   contrary, corroding, corrosive, corrupting, corruptive, crosswise,
   damaging, deadly, deleterious, detrimental, disadvantageous,
   disserviceable, distressing, effete, empty, etiolated, fatuitous,
   fatuous, feckless, fruitless, futile, harmful, hindering,
   hindersome, hurtful, in the way, inadequate, inane, ineffective,
   ineffectual, inefficacious, inhibiting, inhibitive, injurious,
   inoperative, interrupting, interruptive, invalid, lethal, malefic,
   malevolent, malign, malignant, mischievous, noisome, noxious,
   nugacious, nugatory, obstructing, obstructive, obstruent,
   occlusive, of no force, ominous, pernicious, poisonous,
   prejudicial, repressive, restrictive, scatheful, sterile, stifling,
   strangling, suppressive, toxic, troublesome, unavailing, useless,
   vain, venenate, veneniferous, venenous, venomous, vicious,
   virulent