Aspire to jump with energy (4)
I believe the answer is:
hope
'aspire to' is the definition.
(thesaurus)
'jump with energy' is the wordplay.
'jump' becomes 'hop' (hopping is a kind of jumping).
'with' is a charade indicator (letters next to each other).
'energy' becomes 'e' (physics symbol as in E=mc2).
'hop'+'e'='HOPE'
(Other definitions for hope that I've seen before include "Bob --, US comic" , "Trust" , "Cross your fingers" , "Anticipation" , "Feeling of expectation or desire" .)