Got trousers on? Lie! One lacking - if so? (10)
I believe the answer is:
barelegged
'so?' is the definition.
Both the definition and answer are adjectives. Maybe there's an association between them I don't understand?
'got trousers on? lie one lacking' is the wordplay.
I cannot really understand how this works, but
'on?' could be 'leg' (cricket term, fielding positions) and 'leg' is present in the answer.
'one' could be 'a' (a thing is one thing) and 'a' is found in the answer.
This explanation may well be incorrect...
'if' is the link.
Can you help me to learn more?
(Other definitions for barelegged that I've seen before include "in a mini?" , "not wearing stockings?" .)