Source : Webster's Revised Unabridged Dictionary (1913)

Looker \Look"er\, n.
   One who looks.

   {Looker-on}, a spectator; one that looks on, but has no
      agency or part in an affair.

            Did not this fatal war affront thy coast, Yet
            sattest thou an idle looker-on ?      --Fairfax.

Source : WordNet®

looker
     n 1: a close observer; someone who looks at something (such as an
          exhibition of some kind); "the spectators applauded the
          performance"; "television viewers"; "sky watchers
          discovered a new star" [syn: {spectator}, {witness}, {viewer},
           {watcher}]
     2: a very attractive or seductive looking woman [syn: {smasher},
         {stunner}, {knockout}, {beauty}, {ravisher}, {sweetheart},
         {peach}, {lulu}, {mantrap}, {dish}]