Victory gives one Frenchman energy (3)
I believe the answer is:
vim
'energy' is the definition.
(I know that energy can be written as vim)
'victory gives one frenchman' is the wordplay.
I cannot really see how this works, but
'victory' could be 'v' and 'v' is found in the answer.
'one' could be 'i' (Roman numeral) and 'i' is found in the answer.
'frenchman' could be 'm' (abbreviation for Monsieur - like 'Mr') and 'm' 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 vim that I've seen before include "Pep and energy" , "Exuberant vigour" , "Informal energy or drive" , "Liveliness" , "Pep (informal)" .)