Top decision-maker removes four (7)
I believe the answer is:
execute
'top' is the definition.
Although both the answer and definition are verbs in their base form, I don't understand how one could define the other.
'decision-maker removes four' is the wordplay.
'decision maker' becomes 'exec' (I've seen this in another clue).
'removes four' becomes 'ute' (I can't justify this - if you can you should give a lot more credence to this answer).
'exec'+'ute'='EXECUTE'
Can you help me to learn more?
(Other definitions for execute that I've seen before include "Maybe send to chair" , "Carry out - official killing?" , "Finish off" , "Carry into effect" , "Put to death or carry out, say plan" .)