Female, inwardly modest, showing a bit of leg (5)
I believe the answer is:
femur
'a bit of leg' is the definition.
(the femur is a bone of the leg)
'female inwardly modest' is the wordplay.
'female' becomes 'f' (common abbreviation).
'inwardly' means to look at the middle letters (only the letters inside the word are used).
'modest' becomes 'demure' (I've seen this in another clue).
The central letters of 'demure' are 'emur'.
'f'+'emur'='FEMUR'
'showing' acts as a link.
(Other definitions for femur that I've seen before include "Bone in leg" , "Part of leg" , "Large bone" , "Thigh bone" , "Thighbone" .)