The most common and most likely answer to this crossword clue is the 9 letter word CONVOLUTE
I've seen this crossword clue in The Guardian
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Buddy explains!
The straight part
We know that "Roll up /Roll up" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case roll up /roll up = convolute.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CONVOLUTE mean?
CONVOLUTE verb- To make unnecessarily complex.
- To fold or coil into numerous overlapping layers.
- Convoluted.
- (of a leaf) Coiled such that one edge is inside, and one outside the coil, giving a spiral effect in cross section. (A special case of imbricate.)