Empty role crushes first female magistrate (5)
I believe the answer is:
reeve
'magistrate' is the definition.
(type of historical legal official)
'empty role crushes first female' is the wordplay.
'empty role crushes' becomes 're' (I can't explain this - if you can you should give a lot more credence to this answer).
'first female' becomes 'eve' (Adam and Eve).
're'+'eve'='REEVE'
Can you help me to learn more?
(Other definitions for reeve that I've seen before include "Steward who told a Tale" , "One of Chaucer's Canterbury pilgrims" , "Medieval official - pass rope through an eye" , "fasten rope" , "Pass the end of a rope through the bailiff" .)