Lovers wasted energy getting answer (7)
I believe the answer is:
resolve
'answer' is the definition.
(I know that answer can be written as resolve)
'lovers wasted energy getting' is the wordplay.
'wasted' indicates anagramming the letters.
'energy' becomes 'e' (physics symbol as in E=mc2).
'getting' says to put letters next to each other.
'lovers' anagrammed gives 'resolv'.
'resolv'+'e'='RESOLVE'
(Other definitions for resolve that I've seen before include "12 [STIFF UPPER LIP]" , "Settle (a dispute)" , "Be determined" , "Come to a definite conclusion" , "Settle (a matter)" .)