Moonstruck (4)
I believe the answer is:
rapt
'moonstruck' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for rapt that I've seen before include "Part (anag.)" , "Spellbound in part" , "Part of being intent and absorbed" , "Ecstatic in part" , "Engrossed, spellbound" .)