Unexpected spur incited revolt (10)
I believe the answer is:
surprising
'unexpected' is the definition.
(similar in meaning)
'spur incited revolt' is the wordplay.
I cannot really see how this works, but
an anagram of 'spur' is 'surp' which is within the answer.
'revolt' could be 'rising' (synonyms) and 'rising' is found in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for surprising that I've seen before include "Mildly astonishing" , "Causing astonishment" , "Unexpected" .)