Large sea bream tormented ray (5,4)
I believe the answer is:
laser beam
'ray' is the definition.
(laser beam is a kind of ray)
'large sea bream tormented' is the wordplay.
'large' becomes 'l'.
'tormented' is an anagram indicator.
'sea'+'bream'='seabream'
'seabream' anagrammed gives 'aserbeam'.
'l'+'aserbeam'='LASER BEAM'
(Other definitions for laser beam that I've seen before include "Shaft of light or electromagnetic radiation" , "Shaft of light or electro-mechanic radiation" , "Intense ray of light" , "Column of intensified light" , "penetrating light" .)