Supplement energy capacity on ecstasy (3)
I believe the answer is:
eke
'supplement' is the definition.
(I've seen this before)
'energy capacity on ecstasy' is the wordplay.
I cannot really see how this works, but
'energy' could be 'ke' (K.E. is an example) and 'ke' is located in the answer.
'ecstasy' could be 'e' (informal term for the drug) and 'e' is found within the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for eke that I've seen before include "Increase, lengthen" , "long ago" , "To -- out is to add to" , "To -- something out is to make it go further" , "Make a living laboriously - a palindrome" .)