Turnover not very sluggish (5)

I believe the answer is:

inert

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'very sluggish' is the definition.
(I've seen this in another clue)

I cannot understand how the rest of the clue works.

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(Other definitions for inert that I've seen before include "Leaden" , "Incapable of acting, like some gas" , "Motionless or lifeless" , "Without the strength to move" , "'Not moving, lifeless (5)'" .)

I've seen this clue in The Hindu.

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