Mad judge could give such a short sentence (5)
I believe the answer is:
irate
'mad' is the definition.
(I've seen this before)
'judge could give such a short sentence' is the wordplay.
I cannot really understand how this works, but
'judge' could be 'rate' (rating is a kind of judging) and 'rate' is present in the answer.
A single letter 'i' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for irate that I've seen before include "Spitting feathers" , "Magical rod" , "Aggrieved" , "Angry, annoyed" , "Cross, irritated" .)