Source : Webster's Revised Unabridged Dictionary (1913)

Mighty \Might"y\, a. [Compar. {Mightier}; superl. {Mightiest}.]
   [AS. meahtig, mihtig; akin to G. m["a]chtig, Goth. mahteigs.
   See {Might}, n.]
   1. Possessing might; having great power or authority.

            Wise in heart, and mighty in strength. --Job ix. 4.

   2. Accomplished by might; hence, extraordinary; wonderful.
      ``His mighty works.'' --Matt. xi. 20.

   3. Denoting and extraordinary degree or quality in respect of
      size, character, importance, consequences, etc. ``A mighty
      famine.'' --Luke xv. 14. ``Giants of mighty bone.''
      --Milton.

            Mighty was their fuss about little matters.
                                                  --Hawthorne.

Mighty \Might"y\, n.; pl. {Mighties}.
   A warrior of great force and courage. [R. & Obs.] --1 Chron.
   xi. 12.

Mighty \Might"y\, adv.
   In a great degree; very. [Colloq.] ``He was mighty
   methodical.'' --Jeffrey.

         We have a mighty pleasant garden.        --Doddridge.

Source : WordNet®

mighty
     adv : (Southern regional intensive) very; "the baby is mighty
           cute"; "he's mighty tired"; "it is powerful humid";
           "that boy is powerful big now"; "they have a right nice
           place" [syn: {powerful}, {right}]
     [also: {mightiest}, {mightier}]

mighty
     adj : having or showing great strength or force or intensity;
           "struck a mighty blow"; "the mighty logger Paul
           Bunyan"; "the pen is mightier than the sword"-
           Bulwer-Lytton
     [also: {mightiest}, {mightier}]