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One who says a lot about a balloon (6)

Ross

I believe the answer is:

gasbag

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'balloon' is the definition.
(thesaurus)

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(Other definitions for gasbag that I've seen before include "One who talks too much, or a balloon" , "Talkative person or filled balloon" , "One talks at length on boring topics" , "a container of helium" , "An informal blatherer" .)

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