Woman from field hospital (4)
I believe the answer is:
leah
'woman' is the definition.
'field hospital' is the wordplay.
'field' becomes 'lea' (I've seen this before).
'hospital' becomes 'h'.
'lea'+'h'='LEAH'
'from' is the link.
(Other definitions for leah that I've seen before include "her elder sister" , "Jacobs first wife (Gen.29)" , "Jacob's first wife (Bible)" , "Hale (anag) - wife of Jacob" , "Jacob's first wife (Gen. 29)" .)