A needling product, no doubt (6)
I believe the answer is:
stitch
'doubt' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for stitch that I've seen before include "closer" , "Sudden pain in side after exercise" , "Piece of needlework" , "in time one could save many" , "Pain caused by running" .)