Crossword Genius

They contain new form of slang (7)

Ross

I believe the answer is:

flagons

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'they contain new' is the definition.
The definition suggests an adverb but the answer is not.

'form of slang' is the wordplay.
'form' is an anagram indicator.
'of'+'slang'='ofslang'
'ofslang' anagrammed gives 'FLAGONS'.

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(Another definition for flagons that I've seen is " Large bottles".)

I've seen this clue in The Globe and Mail.
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