New lace - it's stretchy (7)
I believe the answer is:
elastic
'stretchy' is the definition.
(something elastic can be stretched)
'new lace it's' is the wordplay.
'new' indicates an anagram.
'lace'+'its'='laceits'
'laceits' is an anagram of 'ELASTIC'.
(Other definitions for elastic that I've seen before include "Material that stretches" , "capable of adapting to change?" , "'Flexible, springy (7)'" , "Springing back to shape after stretching" , "Material for bands" .)