Herb making daughter unwell (4)
I believe the answer is:
dill
'herb' is the definition.
(I know that dill is a type of herb)
'daughter unwell' is the wordplay.
'daughter' becomes 'd' (genealogical abbreviation).
'unwell' becomes 'ill' (similar in meaning).
'd'+'ill'='DILL'
'making' is the link.
(Other definitions for dill that I've seen before include "Herb with thread-like foliage used as seasoning" , "Herb commonly used with gravlax" , "medicinal plant" , "Herb of parsley family" , "Herb; rhymes with beak" .)