The question of who sounds a sorceress? (5)
I believe the answer is:
which
'the question of who' is the definition.
'which' can be an answer for 'the question' (which is a question word). I am not certain of the rest of the definition.
'sounds a sorceress?' is the wordplay.
'sounds' indicates a 'sounds like' (homophone) clue.
'a sorceress?' becomes 'witch' (synonyms).
'witch' is a homophone of 'WHICH'.
Can you help me to learn more?
(Other definitions for which that I've seen before include "Organisation giving information to consumers" , "What one?" , "Consumer magazine" .)