Excite ours somehow with energy (5)
I believe the answer is:
rouse
'excite' is the definition.
(I know that excite can be written as rouse)
'ours somehow with energy' is the wordplay.
'somehow with' indicates an anagram.
'energy' becomes 'e' (physics symbol as in E=mc2).
'ours' anagrammed with 'e' makes 'ROUSE'.
(Other definitions for rouse that I've seen before include "To start" , "Waken" , "Bumper" , "cause to wake or to become active" , "Bestir" .)