The female driver’s first in ditch (4)
I believe the answer is:
shed
'ditch' is the definition.
(both can mean get rid of)
'the female driver's first' is the wordplay.
'the female' becomes 'she' ('she' refers to a woman).
'driver's first' becomes 'd' (1st letter of 'driver').
'she'+'d'='SHED'
'in' acts as a link.
(Other definitions for shed that I've seen before include "Get rid of - hut" , "Discard (something)" , "tools found here?" , "Drop - cast off" , "In which lawnmower is kept" .)