A ‘queen’ may do this with snappy ornamentation (5-5)
I believe the answer is:
cross-dress
'a queen may' is the definition.
Although both the answer and definition are verbs in their base form, I don't understand how they can define each other.
'do this with snappy ornamentation' is the wordplay.
I cannot quite understand how this works, but
'do' could be 'dress' (synonyms) and 'dress' is found in the answer.
'snappy' could be 'cross' (both can mean bad-tempered) and 'cross' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for cross-dress that I've seen is " Wear clothing typical of the opposite sex".)