Source : Webster's Revised Unabridged Dictionary (1913)

Mitigate \Mit"i*gate\, v. t. [imp. & p. p. {Mitigated}; p. pr. &
   vb. n. {Mitigating}.] [L. mitigatus, p. p. of mitigare to
   soften, mitigate; mitis mild, soft + the root of agere to do,
   drive.]
   1. To make less severe, intense, harsh, rigorous, painful,
      etc.; to soften; to meliorate; to alleviate; to diminish;
      to lessen; as, to mitigate heat or cold; to mitigate
      grief.

   2. To make mild and accessible; to mollify; -- applied to
      persons. [Obs.]

            This opinion . . . mitigated kings into companions.
                                                  --Burke.

   Syn: To alleviate; assuage; allay. See {Alleviate}.

Source : WordNet®

mitigated
     adj : made less severe or intense; "he gladly accepted the
           mitigated penalty" [ant: {unmitigated}]