Time sets out trials (5)
I believe the answer is:
tests
'trials' is the definition.
(I know this)
'time sets out' is the wordplay.
'time' becomes 't' (abbreviation).
'out' is an anagram indicator (out can mean wrong or inaccurate).
'sets' is an anagram of 'ests'.
't'+'ests'='TESTS'
(Other definitions for tests that I've seen before include "Trials for cricketers" , "Tries out" , "Trials, exams" , "Major cricket matches" , "Trials -- tribulations" .)