Impressed by energy charge (8)
I believe the answer is:
stampede
'charge' is the definition.
(I've seen this before)
'impressed by energy' is the wordplay.
'impressed' becomes 'stamped' (stamping is a kind of impressing).
'by energy' becomes 'e' (physics symbol as in E=mc2. I am not sure about the 'by' bit.).
'stamped'+'e'='STAMPEDE'
Can you help me to learn more?
(Other definitions for stampede that I've seen before include "Headlong rush of a group in panic" , "Crazy pets made a sudden rush" , "unstable flight" , "Neat rush" , "Deems apt to have flight of cattle" .)