Disappear completely (5)
I believe the answer is:
clear
This clue is a double definition.
'disappear' is the first definition.
(thesaurus)
'completely' is the second definition.
(thesaurus)
(Other definitions for clear that I've seen before include "Transparent - free of obstruction" , "Transparent, easy to see through" , "Lucid, transparent" , "Pellucid" , "Plain; unblock" .)