Magic initially lacking energy takes first shot (6)
I believe the answer is:
pellet
'shot' is the definition.
(synonyms)
'magic initially lacking energy takes first' is the wordplay.
'magic' becomes 'pell' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'initially lacking' means to remove the first letter.
'energy' becomes 'pe' (P.E. is an example).
'takes first' becomes 't' (pst letter of 'takes').
'pe' with its initial letter taken off is 'e'.
'pell'+'e'+'t'='PELLET'
Can you help me to learn more?
(Other definitions for pellet that I've seen before include "Piece of shot for gun" , "Small round ball" , "Small rounded mass" , "A piece of shot from cartridge" , "Small ball of shot" .)