Woman's relative mostly supported by daughter alone (10)
I believe the answer is:
unassisted
'alone' is the definition.
(thesaurus)
'woman's relative mostly supported by daughter' is the wordplay.
'woman's' becomes 'unas'.
'relative mostly supported by daughter' becomes 'sisted' (I can't explain this - if you can you should believe this answer much more).
'unas'+'sisted'='UNASSISTED'
(Other definitions for unassisted that I've seen before include "Getting no help" , "Without help" , "Solo" .)