Aggressive routine is drawback to a new church (3,5)
I believe the answer is:
war dance
'aggressive routine' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'drawback to a new church' is the wordplay.
'drawback' becomes 'ward' (I've seen this in other clues).
'to' says to put letters next to each other.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'church' becomes 'CE' (abbreviation for Church of England).
'ward'+'a'+'n'+'ce'='WAR-DANCE'
'is' acts as a link.
Can you help me to learn more?
(Other definitions for war dance that I've seen before include "Steps taken by fighters" , "Tribal ceremony before battle" , "steps taken before engagement" , "Pre-battle ceremony" , "moves anticipating conflict?" .)