Source : Webster's Revised Unabridged Dictionary (1913)

Hefty \Heft"y\, a.
   Moderately heavy. [Colloq. U. S.]

Source : WordNet®

hefty
     adj 1: (of a person) possessing physical strength and weight;
            rugged and powerful; "a hefty athlete"; "a muscular
            boxer"; "powerful arms" [syn: {brawny}, {muscular}, {powerful},
             {sinewy}]
     2: of considerable weight and size; "a hefty dictionary"
     3: large in amount or extent or degree; "it cost a considerable
        amount"; "a goodly amount"; "received a hefty bonus"; "a
        respectable sum"; "a tidy sum of money"; "a sizable
        fortune" [syn: {goodly}, {goodish}, {respectable}, {sizable},
         {sizeable}, {tidy}]
     [also: {heftiest}, {heftier}]