Stretchy lace - it's broken (7)
I believe the answer is:
elastic
'stretchy' is the definition.
(something elastic can be stretched)
'lace it's broken' is the wordplay.
'broken' indicates an anagram.
'lace'+'its'='laceits'
'laceits' anagrammed gives 'ELASTIC'.
(Other definitions for elastic that I've seen before include "Springy, like a rubber band" , "Cats lie (anag.)" , "It's lace (anag.)" , "Something stretchy" , "Stretcher" .)