Accomplished teacher has energy (4)
I believe the answer is:
done
'accomplished' is the definition.
(to do something is to accomplish it)
'teacher has energy' is the wordplay.
'teacher' becomes 'don' (don is a kind of teacher).
'has' says to put letters next to each other.
'energy' becomes 'e' (physics symbol as in E=mco).
'don'+'e'='DONE'
(Other definitions for done that I've seen before include "Tricked" , "Finished like node" , "(Of food) well cooked" , "Robbed" , "Achieved" .)