Loose board banging in jumbo (14)

I believe the answer is:

brobdingnagian

'jumbo' is the definition.
(thesaurus)

'loose board banging in' is the wordplay.
'loose' indicates anagramming the letters (letters are loosened from their original positions).
'board'+'banging'+'in'='boardbangingin'
'boardbangingin' is an anagram of 'BROBDINGNAGIAN'.

(Another definition for brobdingnagian that I've seen is " Born big".)

I've seen this clue in the Sydney Morning Herald.

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