Source : Webster's Revised Unabridged Dictionary (1913)

Woolgathering \Wool"gath`er*ing\, n.
   Indulgence in idle imagination; a foolish or useless pursuit
   or design.

         His wits were a woolgathering, as they say. --Burton.

Woolgathering \Wool"gath`er*ing\, a.
   Indulging in a vagrant or idle exercise of the imagination;
   roaming upon a fruitless quest; idly fanciful.

Source : WordNet®

woolgathering
     adj : dreamy in mood or nature; "a woolgathering moment" [syn: {dreamy},
            {moony}]
     n : an idle indulgence in fantasy