Wholly engrossed (4)
I believe the answer is:
rapt
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">wholly engrossed</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for rapt that I've seen before include "Spellbound, enthralled" , "Part of being intent and absorbed" , "Ecstatic - engrossed" , "Spellbound in part" , "riveted" .)