Charged up - wicked! (4)
I believe the answer is:
evil
'wicked' is the definition.
('evil' is associated in meaning with 'wicked')
'charged up' is the wordplay.
'charged' becomes 'live' (I've seen this in other clues).
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'live' reversed gives 'EVIL'.
(Other definitions for evil that I've seen before include "Wicked or immoral" , "Profoundly wicked" , "Villainy" , "Extremely wicked" , "Unholy" .)