What has one spinning round ending with car crashing (4,5)
I believe the answer is:
'what has one spinning round' is the definition.
(dance in a circle)
'ending with car crashing' is the wordplay.
'with' means one lot of letters go next to another.
'crashing' is an anagram indicator.
'ending' after 'car' is 'carending'.
'carending' with letters rearranged gives 'RING DANCE'.