Judgement a test could reveal (5)
I believe the answer is:
taste
'judgement' is the definition.
(thesaurus)
'a test could reveal' is the wordplay.
'a test' anagrams to 'TASTE'.
Though, I'm not clear how the anagram is indicated.
Can you help me to learn more?
(Other definitions for taste that I've seen before include "Savour; discernment" , "Show sense" , "Flavour or discrimination" , "Experience - discrimination" , "Sample, savour" .)