Homeless or neglected child (4)
I believe the answer is:
waif
'homeless or neglected child' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for waif that I've seen before include "Neglected, homeless child" , "Someone very thin or underfed" , "Ragamuffin" , "An unowned or abandoned child" , "Gamin" .)