Stress involving one daughter in casualty (8)
I believe the answer is:
accident
'casualty' is the definition.
(thesaurus)
'stress involving one daughter' is the wordplay.
'stress' becomes 'accent' (accent can mean to emphasise or stress).
'involving' means one lot of letters goes inside another.
'one' becomes 'i' (Roman numeral).
'daughter' becomes 'd' (genealogical abbreviation).
'i'+'d'='id'
'accent' going around 'id' is 'ACCIDENT'.
'in' acts as a link.
(Other definitions for accident that I've seen before include "Chance event with no apparent cause" , "Chance misfortune or injury" , "Unfortunate unintentional incident" , "Prang" , "Fortune" .)