The Collaborative International Dictionary of English v.0.48:

make-believe \make"-be*lieve`\, n.
   A feigning to believe, as in the play of children; a mere
   pretense; a fiction; an invention. "Childlike make-believe."
   --Tylor.
   [1913 Webster]

         To forswear self-delusion and make-believe. --M.
                                                  Arnold.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Make-believe \Make"-be*lieve`\, a.
   1. Feigned; insincere. "Make-believe reverence." --G. Eliot.
      [1913 Webster]

   2. Imaginary; as, the child had a make-believe friend to whom
      he often talked.
      [PJC]

WordNet (r) 3.0 (2006):

make-believe
    adj 1: imagined as in a play; "the make-believe world of
           theater"; "play money"; "dangling their legs in the water
           to catch pretend fish" [syn: make-believe, pretend]
    n 1: imaginative intellectual play [syn: pretense, pretence,
         make-believe]
    2: the enactment of a pretense; "it was just pretend" [syn:
       make-believe, pretend]