Boil these, exploding with energy (6)
I believe the answer is:
seethe
'boil' is the definition.
('seethe' can be a synonym of 'boil')
'these exploding with energy' is the wordplay.
'exploding with' indicates anagramming the letters.
'energy' becomes 'e' (physics symbol as in E=mc2).
'these' anagrammed with 'e' can make 'SEETHE'.
(Other definitions for seethe that I've seen before include "(Of liquid) move as if boiling" , "Boil or become very angry" , "Bubble, almost boil" , "get very agitated" , "Be extremely angry" .)