Source : Webster's Revised Unabridged Dictionary (1913)

Inconsiderate \In`con*sid"er*ate\, a. [L. inconsideratus. See
   {In-} not, and {Considerate}.]
   1. Not considerate; not attentive to safety or to propriety;
      not regarding the rights or feelings of others; hasty;
      careless; thoughtless; heedless; as, the young are
      generally inconsiderate; inconsiderate conduct.

            It is a very unhappy token of our corruption, that
            ther? should be any so inconsiderate among us as to
            sacrifice morality to politics.       --Addison.

   2. Inconsiderable. [Obs.] --E. Terry.

   Syn: Thoughtless; inattentive; inadvertent; heedless;
        negligent; improvident; careless; imprudent; indiscreet;
        incautious; injudicious; rash; hasty.

Source : WordNet®

inconsiderate
     adj 1: lacking regard for the rights or feelings of others;
            "shockingly inconsiderate behavior" [ant: {considerate}]
     2: without proper consideration or reflection; "slovenly
        inconsiderate reasoning"; "unconsidered words"; "prejudice
        is the holding of unconsidered opinions" [syn: {unconsidered}]