Maiden having opportunity to discard old slipper (8)
I believe the answer is:
moccasin
'slipper' is the definition.
(type of slipper)
'maiden having opportunity to discard old' is the wordplay.
I cannot really see how this works, but
'maiden' could be 'm' (cricket abbreviation) and 'm' is found in the answer.
'opportunity' could be 'in' (in can mean an opportunity or way into something) and 'in' is located in the answer.
'old' could be 'o' (common abbreviation eg in OE for Old English) and 'o' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for moccasin that I've seen before include "Soft leather shoe - venomous snake" , "Soft, slip-on shoe - snake" , "going on foot?" , "Sonic mac (anag.)" , "American Indian shoe" .)