Shreds rates into pieces (5)
I believe the answer is:
tears
'shreds' is the definition.
(I've seen this in another clue)
'rates into pieces' is the wordplay.
'into pieces' indicates an anagram (I've seen this in other clues).
'rates' with letters rearranged gives 'TEARS'.
(Other definitions for tears that I've seen before include "Rips with signs of sorrow" , "charges" , "emotional reaction!" , "Water in eyes" , "Moves very quickly" .)