Such changes effected by new broom? (8)
I believe the answer is:
sweeping
'such' is the definition.
Both the answer and definition are adjectives. Perhaps you can see a link between them that I can't see?
'changes effected by new broom?' is the wordplay.
I cannot quite understand how this works, but
'new' could be 'n' (common abbreviation eg NT for New Testament) and 'n' is present in the answer.
'broom?' could be 'sweep' ('sweep' can be a synonym of 'broom') and 'sweep' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for sweeping that I've seen before include "work for Mrs Mopp" , "Wide-ranging and comprehensive - also cleaning?" , "Raising a dust" , "Brushing or ignoring distinctions" , "all-encompassing" .)