Plant cutter of great power? (5)
I believe the answer is:
laser
'plant cutter' is the definition.
'laser' can be an answer for 'cutter' (lasers can cut things). I'm not certain of the 'plant' bit.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for laser that I've seen before include "Optical device producing an intense beam of light" , "Device that produces an intense beam of light" , "Device for concentrating light" , "Intense light generator" , "scientific device" .)