Brown cut short demagogue's childish outburst (7)
I believe the answer is:
tantrum
'childish outburst' is the definition.
(I've seen this before)
'brown cut short demagogue's' is the wordplay.
I cannot really understand how this works, but
'brown' could be 'tan' (tan is a kind of brown) and 'tan' is found in the answer.
'short' could be 'rum' (short can mean an alcoholic drink) and 'rum' is located in the answer.
A single letter 't' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for tantrum that I've seen before include "petulant outburst" , "Childish display of temper" , "Child's outburst of bad temper" , "Paddy" , "Childish fit of anger" .)