The Collaborative International Dictionary of English v.0.48:

Inconvenient \In`con*ven"ient\, a. [L. inconveniens unbefitting:
   cf. F. inconv['e]nient. See In- not, and Convenient.]
   [1913 Webster]
   1. Not becoming or suitable; unfit; inexpedient.
      [1913 Webster]

   2. Not convenient; giving trouble, uneasiness, or annoyance;
      hindering progress or success; uncomfortable;
      disadvantageous; incommodious; inopportune; as, an
      inconvenient house, garment, arrangement, or time.

   Syn: Unsuitable; uncomfortable; disaccommodating; awkward;
        annoying; unseasonable; inopportune; incommodious;
        disadvantageous; troublesome; cumbersome; embarrassing;
        objectionable.
        [1913 Webster]

WordNet (r) 3.0 (2006):

inconvenient
    adj 1: not suited to your comfort, purpose or needs; "it is
           inconvenient not to have a telephone in the kitchen";
           "the back hall is an inconvenient place for the
           telephone" [ant: convenient]
    2: not conveniently timed; "an early departure is inconvenient
       for us"

Moby Thesaurus II by Grady Ward, 1.0:

69 Moby Thesaurus words for "inconvenient":
   annoying, awkward, bothersome, bulky, burdensome, clumsy, contrary,
   crosswise, cumbersome, detrimental, disadvantageous, discommodious,
   disturbing, embarrassing, hulking, hulky, ill-considered,
   ill-seasoned, ill-timed, impractical, improper, inappropriate,
   inauspicious, incommodious, inexpedient, infelicitous, inopportune,
   intempestive, intrusive, irksome, irrelevant, irritating, late,
   mal a propos, malapropos, mistimed, off base, onerous, out of line,
   out of phase, out of time, perverse, pestiferous, ponderous,
   prejudicial, premature, too late, too soon, troublesome,
   unbefitting, unfavorable, unfit, unfitting, unfortunate, unhandy,
   unhappy, unlucky, unmanageable, unpropitious, unready, unripe,
   unseasonable, unsettling, unsuitable, untimely, untoward, unwieldy,
   upsetting, wrong