Direct hit for a speculator (4)
I believe the answer is:
bull
'for a speculator' is the definition.
(I've seen this in other clues)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for bull that I've seen before include "Bovine charger?" , "Cow's mate" , "fifty on board" , "Tripe" , "Papal edict - nonsense" .)