Strand unwound from ball left on court (4)
I believe the answer is:
wool
'strand unwound from ball' is the definition.
I can't tell whether this defines the answer.
'left on court' is the wordplay.
'left' becomes 'l' (common abbreviation).
'on' means one lot of letters go next to another.
'court' becomes 'woo' (both can mean to romance someone).
'l' put after 'woo' is 'WOOL'.
Can you help me to learn more?
(Other definitions for wool that I've seen before include "Sheep's coat" , "Fabric from fleece" , "Where the Lord Chancellor sits" , "Yarn for knitting" , "Fleece of sheep" .)