Female prisoner to tire (4)
I believe the answer is:
flag
'to tire' is the definition.
(I've seen this in another clue)
'female prisoner' is the wordplay.
'female' becomes 'f' (common abbreviation).
'prisoner' becomes 'lag' (slang term).
'f'+'lag'='FLAG'
(Other definitions for flag that I've seen before include "sink" , "Colours a paving stone" , "Iris; pennant" , "what Amundsen planted" , "Draw attention to" .)