Decorating requires a pronounced start (8)
I believe the answer is:
adorning
'decorating' is the definition.
('adorn' can be a synonym of 'decorate')
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for adorning that I've seen before include "decking" , "Decorating with ornaments" , "Decorating, embellishing" .)