Caught, a spy is hidden in undergarment (8)
I believe the answer is:
camisole
'undergarment' is the definition.
(camisole is a kind of undergarment)
'caught a spy is hidden' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'spy' becomes 'mole' (mole is a kind of spy).
'hidden' indicates putting letters inside.
'mole' enclosing 'is' is 'misole'.
'c'+'a'+'misole'='CAMISOLE'
'in' is the link.
(Other definitions for camisole that I've seen before include "Close aim (anag.)" , "Loose underbodice" , "Loose undergarment" , "Short undergarment for women" , "Item of lingerie" .)