Crack soldiers in centre of Exeter in gear (9)
I believe the answer is:
equipment
'gear' is the definition.
(I've seen this in another clue)
'crack soldiers in centre of exeter' is the wordplay.
'crack' becomes 'quip' (both can mean a joke).
'soldiers' becomes 'men' (men can mean a group of soldiers).
'in' indicates putting letters inside.
'centre of' means to look at the middle letters.
The middle letters of 'exeter' are 'et'.
'quip'+'men'='quipmen'
'quipmen' inserted into 'et' is 'EQUIPMENT'.
'in' acts as a link.
(Other definitions for equipment that I've seen before include "Set of instruments that perform a service" , "Apparatus, tools" , "fitting" , "Kit, apparatus" , "Stuff" .)