Savage not in tribunal arranged (6)
I believe the answer is:
brutal
'savage' is the definition.
(I've seen this before)
'not in tribunal arranged' is the wordplay.
'not' indicates named letters should be taken away.
'arranged' is an anagram indicator.
'tribunal' with 'in' removed is 'trbual'.
'trbual' is an anagram of 'BRUTAL'.
(Other definitions for brutal that I've seen before include "Savage and cruel" , "Cruel, animal-like" , "Very cruel and beastly" , "Very cruel, merciless" , "Cruel and unfeeling like an animal" .)