Woolgathering /(?)/

Wool·gath·er·ing

Woolgathering

a.
  1. Indulging in a vagrant or idle exercise of the imagination; roaming upon a fruitless quest; idly fanciful.

Woolgathering

n.
  1. Indulgence in idle imagination; a foolish or useless pursuit or design.
    His wits were a woolgathering, as they say.