Once more haul a bull provocation (3,3)
I believe the answer is:
red rag
'a bull provocation' is the definition.
The definition suggests a singular noun which matches the answer. I also know that 'provocation' relates to this answer.
'once more haul' is the wordplay.
'once more' becomes 're' (prefix in words like 're-emerge' or 're-enter').
'haul' becomes 'drag' (synonyms).
're'+'drag'='RED RAG'
Can you help me to learn more?
(Other definitions for red rag that I've seen before include "It is offensive to a bull" , "Source of extreme provocation" , "might attract a charge" , "Bull incitor?" , "Something proverbially annoying a bull" .)