Joe leaps on and off vehicle GIs use? (4)

I believe the answer is:

jeep

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'vehicle gis use?' is the definition.
I can't judge whether this definition defines the answer.

'joe leaps on and off' is the wordplay.
'on and off' means one should take alternating letters (letters selected on and off at regular intervals).
'joe'+'leaps'='joeleaps'
The alternate letters of 'joeleaps' are 'JEEP'.

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(Other definitions for jeep that I've seen before include "Vehicle for rough terrain" , "Truck" , "Army vehicle, 4-wheel drive" , "Small four-wheel drive vehicle" , "US army car" .)

I've seen this clue in The Times.

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