The Collaborative International Dictionary of English v.0.48:

Inexact \In`ex*act"\, a. [Pref. in- not + exact: cf. F.
   inexact.]
   Not exact; not precisely correct or true; inaccurate.
   [1913 Webster]

WordNet (r) 3.0 (2006):

inexact
    adj 1: not exact [ant: exact]

Moby Thesaurus II by Grady Ward, 1.0:

105 Moby Thesaurus words for "inexact":
   adulterated, aleatoric, aleatory, amorphous, approximate,
   approximative, blemished, blobby, blurred, blurry, broad, chance,
   chancy, chaotic, confused, damaged, defective, deficient,
   disordered, erroneous, fallacious, fallible, false, faulty, foggy,
   found wanting, fuzzy, general, hazy, hit-or-miss, ill-defined,
   immature, impaired, imperfect, imprecise, impure, inaccurate,
   inadequate, inchoate, incoherent, incomplete, incorrect,
   indecisive, indefinable, indefinite, indeterminable, indeterminate,
   indistinct, lacking, lax, loose, makeshift, mediocre, mixed,
   muddled, negligent, nonspecific, not perfect, obscure, off,
   orderless, out of line, out of plumb, out of square, out of true,
   partial, patchy, random, shadowed forth, shadowy, shapeless, short,
   sketchy, stochastic, sweeping, unclear, unconscientious,
   uncritical, undefined, undestined, undetermined, undeveloped,
   uneven, unexacting, unfactual, unfinical, unfinished, unfussy,
   unmeticulous, unpainstaking, unparticular, unperfected, unplain,
   unprecise, unpunctilious, unpunctual, unrigorous, unscrupulous,
   unsound, unspecified, unthorough, vague, veiled, wanting, wrong