Having powerful weapons, some Israel cunningly concealed in turn (7)
I believe the answer is:
nuclear
'having powerful weapons' is the definition.
(nuclear can mean possessing nuclear weapons)
'some israel cunningly concealed in turn' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'in turn' says the letters should be written in reverse (letters turning around).
'raelcun' is hidden in the letters of 'israel cunningly concealed'.
'raelcun' backwards is 'NUCLEAR'.
(Other definitions for nuclear that I've seen before include "Relating to atom energy" , "and 6 Down: Power producer" , "Concerning subatomic particles" , "source of energy" , "Relating to part of atom" .)