Carelessly tear standard (4)
I believe the answer is:
rate
'standard' is the definition.
(I've seen this in other clues)
'carelessly tear' is the wordplay.
'carelessly' indicates an anagram.
'tear' anagrammed gives 'RATE'.
(Other definitions for rate that I've seen before include "Think highly of; criticise severely" , "Be worthy of; speed" , "Velocity" , "Grade or evaluate" , "The number of times something happens in a given period" .)