Its lace could become flexible (7)
I believe the answer is:
elastic
'flexible' is the definition.
(I know that flexible can be written as elastic)
'its lace could become' is the wordplay.
'could become' is an anagram indicator.
'its'+'lace'='itslace'
'itslace' with letters rearranged gives 'ELASTIC'.
(Other definitions for elastic that I've seen before include "Like some bands" , "Narrow strip of rubber" , "Springing back to shape after stretching" , "Something stretchy" , "Flexible (material)" .)