Acrobat bum-over-hip in roll (12)

'acrobat' is the definition.
Both the definition and answer are singular nouns.
Maybe there's an association between them I don't understand?

'bum-over-hip in roll' is the wordplay.
I cannot really understand how this works, but
'bum' could be 'tramp' (synonyms) and 'tramp' is found within the answer.
'over' could be 'o' (cricket abbreviation) and 'o' is found in the answer.
'hip' could be 'in' (both can mean fashionable) and 'in' is located in the answer.
'roll' could be 'list' (list can mean to lean or roll) and 'list' is located in the remaining letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?