Accomplice’s job — mainly to steal ring on time (6)
I believe the answer is:
cohort
'accomplice's' is the definition.
(thesaurus)
'job mainly to steal ring on time' is the wordplay.
'job' becomes 'chore' (synonyms).
'mainly' means to remove the last letter.
'to steal' is an insertion indicator.
'ring' becomes 'o'.
'on time' becomes 't' (abbreviation. I am not sure about the 'on' bit.).
'chore' with its last letter taken away is 'chor'.
'chor' placed around 'o' is 'cohor'.
'cohor'+'t'='COHORT'
Can you help me to learn more?
(Other definitions for cohort that I've seen before include "Ancient Roman military unit" , "troops" , "One of ten in a Roman Legion" , "Warrior band (orig. legion section)" , "Group of similar people" .)