im·pair /im-'per/ vt1: to damage or make worse by or as if by diminishingimpair ed health2: to diminish the value of (property or property rights); specif: to diminish the value of (legal contractual obligations) to the point that a party loses the benefit of the contract or the contract otherwise becomes invalida law impair ing a state's own obligations was entitled to less deference — Gerald Gunther see also contract clauseim·pair·ment n
Merriam-Webster’s Dictionary of Law. Merriam-Webster. 1996.
adulterate, affect injuriously, blight, blunt, contaminate, cripple, crumble, damage, debilitare. debilitate, decrease in excellence, demolish, deplete, deprive of power, desecrate, devalue, dilapidate, diminish, diminish in quality, dissipate, disturb, dull, enervate, enfeeble, erode, frangere, harm, hinder, hurt, imminuere, injure, lessen in power, lessen in value, make inroads on, make worse, mar, obtund, paralyze, pollute, put out of commission, reduce, relax, render feeble, ruin, sap, stifle, taint, undermine, unhinge, waste, weaken, wear out, worsen
associated concepts: impairing the obligation of contracts, impairment of capital, impairment of good will, impairment of memory, impairment of powers, impairment of security
abrogate (annul), adulterate, aggravate (exacerbate), check (restrain), contaminate, damage, debase, debilitate, deface, denature, disable, disadvantage, disorient, endanger, eviscerate, harm, hinder, impede, infect, maim, mistreat, mutilate, pollute, prejudice (injure), spoil (impair), stain, subvert, vitiate
Burton's Legal Thesaurus. William C. Burton. 2006
v. Of property or a contractual right, to interfere in such a way as to diminish its value.
Webster's New World Law Dictionary. Susan Ellis Wild. 2000.