Judgement I must leave unvoiced (4)
I believe the answer is:
tact
'judgement' is the definition.
(thesaurus)
'i must leave unvoiced' is the wordplay.
'must leave' suggests deleting specific letters.
'unvoiced' becomes 'tacit' (I've seen this before).
'tacit' with 'i' taken out is 'TACT'.
(Other definitions for tact that I've seen before include "Consideration in dealing with others" , "Sensitivity in dealing with people" , "Consideration and sensitivity" , "Sensitivity in dealings" , "Understanding" .)