Empty victory gives a feline energy (6)
I believe the answer is:
vacate
'empty' is the definition.
(I know that empty can be written as vacate)
'victory gives a feline energy' is the wordplay.
I cannot really understand how this works, but
'victory' could be 'v' and 'v' is found within the answer.
'a' is present in the answer.
'feline' could be 'cat' (cat is a kind of feline) and 'cat' is found in the answer.
'energy' could be 'e' (physics symbol as in E=mc2) and 'e' is found in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for vacate that I've seen before include "Caveat - cease to occupy" , "Move out and leave empty" , "Clear out and leave empty" , "Leave (a position)" , "Depart from, leave empty" .)