Material needs yarn left over? Not initially (5)
I believe the answer is:
nylon
'material' is the definition.
(nylon is a kind of material)
'needs yarn left over? not initially' is the wordplay.
'initially' suggests taking the first letters.
The first letters of 'needs yarn left over not' is 'NYLON'.
(Other definitions for nylon that I've seen before include "Hose" , "Man-made material" , "Fibrous material" , "The first synthetic fibre" , "may be damaged by running" .)