Blue-grey female trousers not paid for (8)
I believe the answer is:
gunmetal
'blue-grey' is the definition.
I can't tell whether this definition defines the answer.
'female trousers not paid for' is the wordplay.
'female' becomes 'gal' (gal is a kind of female).
'trousers' means one lot of letters goes inside another (trouser can mean to steal or take).
'not' becomes 'un' (prefix meaning 'not').
'paid for' becomes 'met' (eg a rent payment might be met).
'un'+'met'='unmet'
'gal' enclosing 'unmet' is 'GUNMETAL'.
Can you help me to learn more?
(Another definition for gunmetal that I've seen is " sheeny colour".)