Laid-back desire inspiring one on the grog reserves? (7)

I believe the answer is:

militia

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'reserves?' is the definition.
(synonyms)

I cannot understand how the rest of the clue works.

(Other definitions for militia that I've seen before include "Civilian army force" , "Home Guard" , "Citizen army" , "Force raised for emergency" , "Fighting force of civilians" .)

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

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