A word of warning — daughter has very negative emotion (6)
I believe the answer is:
danger
'a word of warning' is the definition.
'daughter has very negative emotion' is the wordplay.
'daughter' becomes 'd'.
'has' means one lot of letters go next to another.
'very negative emotion' becomes 'anger'.
'd'+'anger'='DANGER'
(Other definitions for danger that I've seen before include "Ranged about in some peril" , "Peril, threat" , "Peril in garde" , "Insecurity" , "'Peril, risk (6)'" .)