Where a bad lie, of course, is approximate? (5)

I believe the answer is:

rough

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'is approximate?' is the definition.
(thesaurus)

I cannot understand how the remainder of the clue works.

(Other definitions for rough that I've seen before include "Uneven - approximate - stormy" , "Imprecise" , "Boisterous; uneven" , "Rasping" , "Drivers try to steer clear of this" .)

I've seen this clue in the Evening Standard.

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