What's roguish about Liberal showing no originality? (9)

I believe the answer is:

slavishly

'showing no originality?' is the definition.

'what's roguish about liberal' is the wordplay.
'what's roguish' becomes 'sly'.
'about' is an insertion indicator.
'liberal' becomes 'lavish'.
'sly' enclosing 'lavish' is 'SLAVISHLY'.

I've seen this clue in The Guardian.

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