The Collaborative International Dictionary of English v.0.48:

Fool \Fool\, v. i. [imp. & p. p. Fooled; p. pr. & vb. n.
   Fooling.]
   To play the fool.
   [1913 Webster]

   2. To waste time in unproductive activity; to spend time in
      idle sport or mirth; to trifle; to toy.

   Syn: fool around.
        [PJC]

              Is this a time for fooling?         --Dryden.
        [1913 Webster]

WordNet (r) 3.0 (2006):

fooling
    adj 1: characterized by a feeling of irresponsibility; "a broken
           back is nothing to be casual about; it is no fooling
           matter" [syn: fooling, casual]