Untie (7)
'untie' is the definition.
(thesaurus)
This is all the clue.
(Other definitions for release that I've seen before include "Free from confinement" , "New film" , "put out" , "Issue" , "Liberate" .)
'untie' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for loosen that I've seen before include "Make less tight, slacken" , "Undo a little" , "Relax the tension" , "relax or tear apart" , "Undo, make less tight" .)