Source : Webster's Revised Unabridged Dictionary (1913)

Sunny \Sun"ny\, a. [Compar. {Sunnier}; superl. {Sunniest}.]
   1. Of or pertaining to the sun; proceeding from, or
      resembling the sun; hence, shining; bright; brilliant;
      radiant. ``Sunny beams.'' --Spenser. ``Sunny locks.''
      --Shak.

   2. Exposed to the rays of the sun; brightened or warmed by
      the direct rays of the sun; as, a sunny room; the sunny
      side of a hill.

            Her blooming mountains and her sunny shores.
                                                  --Addison.

   3. Cheerful; genial; as, a sunny disposition.

            My decayed fair A sunny look of his would soon
            repair.                               --Shak.

Source : WordNet®

sunny
     adj 1: abounding with sunlight; "a bright sunny day"; "one shining
            norming"- John Muir; "when it is warm and shiny" [syn:
             {bright}, {shining}, {shiny}, {sunshiny}]
     2: bright and pleasant; promoting a feeling of cheer; "a cheery
        hello"; "a gay sunny room"; "a sunny smile" [syn: {cheery},
         {gay}]
     [also: {sunniest}, {sunnier}]

sunnier
     See {sunny}