Banner -- I boo Stalin rebelliously holding it (12)
I believe the answer is:
abolitionist
'banner' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'i boo stalin rebelliously holding it' is the wordplay.
'rebelliously' is an anagram indicator.
'holding' indicates putting letters inside.
'i'+'boo'+'stalin'='iboostalin'
'iboostalin' with letters rearranged gives 'abolionist'.
'abolionist' going around 'it' is 'ABOLITIONIST'.
Can you help me to learn more?
(Other definitions for abolitionist that I've seen before include "Reformer (eg Wilberforce)" , "One against, eg, slavery" , "Anti-slavery campaigner" , "One favouring end of capital punishment" .)