Loosened, opened (5)
I believe the answer is:
undid
This clue is a double definition.
'loosened' is the first definition.
(I've seen this in another clue)
'opened' is the second definition.
(I've seen this in another clue)
(Other definitions for undid that I've seen before include "Released" , "Cancelled - destroyed" , "Cancelled, reversed (an action)" , "solved knotty problem" , "Reversed, destroyed" .)