Source : WordNet®

big deal
     n 1: an important influential person; "he thinks he's a big
          shot"; "she's a big deal in local politics"; "the Qaeda
          commander is a very big fish" [syn: {big shot}, {big gun},
           {big wheel}, {big cheese}, {big enchilada}, {big fish},
           {head honcho}]
     2: anything of great importance or consequence