Animal gives party energy (3)
I believe the answer is:
'animal' is the definition.
(doe is a kind of animal)
'party energy' is the wordplay.
'party' becomes 'do' (do is a kind of party).
'energy' becomes 'e' (physics symbol as in E=mc2).
'gives' is the link.
(Other definitions for doe that I've seen before include "A female deet", "Feminine counterpart of stag", "Female kangaroo", "Female creature", "Mummy rabbit".)