Arrogant and irreverent embracing Queen (9)
I believe the answer is:
imperious
'arrogant' is the definition.
(I've seen this before)
'irreverent embracing queen' is the wordplay.
'irreverent' becomes 'impious' ('impious' can be similar in meaning to 'irreverent').
'embracing' means one lot of letters goes inside another.
'queen' becomes 'er' (abbreviation for Elizabeth Regina).
'impious' enclosing 'er' is 'IMPERIOUS'.
'and' acts as a link.
(Other definitions for imperious that I've seen before include "high-handed" , "Arrogant, domineering" , "Bossy" , "Haughty - domineering" .)