Fantasising (8)
I believe the answer is:
dreaming
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">fantasising</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for dreaming that I've seen before include "Having fantasies about Niger Dam" , "Fantasising" , "form of idealism?" , "'I'm ... of a white Christmas' (song)" , "In reverie" .)