Criminal losing old female guard (6)

I believe the answer is:

fender

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'criminal losing old female guard' is the definition.
'fender' can be an answer for 'guard' (fender is a kind of guard). I'm not sure about the 'criminal losing old female' bit.

'female guard' is the wordplay.
'female' becomes 'f' (abbreviation).
'guard' becomes 'ender' (I can't justify this - if you can you should believe this answer much more).
'f'+'ender'='FENDER'

Can you help me to learn more?

(Other definitions for fender that I've seen before include "On a boat, it's protects against impact" , "Ship's impact absorber" , "Ship's impact protector" , "Fire- or wheel-guard" , "Hearth-guard" .)

I've seen this clue in The Sun and The Guardian.

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