Ceremony with a severe style (9)
I believe the answer is:
pompadour
'style' is the definition.
(I know that pompadour is a style)
'ceremony with a severe' is the wordplay.
'ceremony' becomes 'pomp' (I've seen this before).
'with' says to put letters next to each other.
'severe' becomes 'dour' (I've seen this in other clues).
'pomp'+'a'+'dour'='POMPADOUR'
(Other definitions for pompadour that I've seen before include "Lady" , "twenty down [HAIRDO]" , "Hairstyle associated with a mistress of Louis XV" , "18th century hairstyle employing a pad at the front to add bulk" , "18th century women's hairstyle" .)