He certainly aims for the bull (7)
I believe the answer is:
matador
'the bull' is the definition.
The definition and answer can be both people as well as being singular nouns.
I also know that 'bull' relates to this answer.
'he certainly aims' is the wordplay.
I cannot quite see how this works, but
'he' could be 'mata' and 'mata' is present in the answer.
The remaining letters 'dor' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'for' acts as a link.
Can you help me to learn more?
(Other definitions for matador that I've seen before include "Principal bullfighter" , "The one who kills the bull" , "One in the ring" , "paid killer" , "Spaniard that fights" .)