Careless pedestrian may be so enervated (3,4)
I believe the answer is:
run down
'enervated' is the definition.
(thesaurus)
'careless pedestrian may be' is the wordplay.
I cannot really see how this works, but
'be' could be 'run' (running is a kind of being) and 'run' is found within the answer.
The remaining letters 'down' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'so' is the link.
Can you help me to learn more?
(Other definitions for run down that I've seen before include "In a neglected state" , "Worn-out" , "Cut back on" , "Drained" , "brief summary" .)