Line in which cop moves with caution (10)
I believe the answer is:
occupation
'line' is the definition.
(I know that line can be written as occupation)
'cop moves with caution' is the wordplay.
'moves with' indicates an anagram.
'cop' anagrammed with 'caution' gives 'OCCUPATION'.
'in which' acts as a link.
(Other definitions for occupation that I've seen before include "Business - residence" , "end of invasion?" , "the seizure and control of a foreign territory" , "Calling" , "Doctor, for instance" .)