Extraordinary rear girl jiggles around for all to see (9)
I believe the answer is:
irregular
'extraordinary' is the definition.
(thesaurus)
'rear girl jiggles around for all to see' is the wordplay.
I cannot really see how this works, but
'girl' could be 'ula' and 'ula' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for irregular that I've seen before include "Unpredictable" , "Rough - dishonest" , "unprincipled" , "Unconventional" , "somewhat odd" .)