Cutting edge round old empty cask causes closure (8)
I believe the answer is:
blockade
'closure' is the definition.
(thesaurus)
'cutting edge round old empty cask' is the wordplay.
'cutting edge' becomes 'blade' (I've seen this before).
'round' means one lot of letters goes inside another.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'empty' says to hollow out the word (remove centre letters).
'cask' with its centre taken out is 'ck'.
'o'+'ck'='ock'
'blade' enclosing 'ock' is 'BLOCKADE'.
'causes' is the link.
(Other definitions for blockade that I've seen before include "Action taken to prevent entry as of goods" , "Military restriction of access" , "Cut off" , "Siege" , "The sealing off a place to prevent entry or exist" .)