accomplice

1. (law) An associate in the commission of a crime; a participator in an offense, whether a principal or an accessory.Examples: "Childleſs Arturius, vaſtly rich before, / Thus by his Loſſes multiplies his Store: / Suſpected for Accomplice to the Fire, / That burnt his Palace but to build it higher."; "And thou, the curs’d Accomplice of her Treaſon, / Declare thy Meſſage, and expect thy Doom."; "“You have a young son, yet you involve yourself in the world of organised crime. Robbing a bank no less! Stealing half a million pounds! Money, I might add, that has never been recovered. You must know where the money is hidden, and yet, Mr Goodie, you refuse to inform the police. You must have had accomplices, but you will not name them. This no doubt is the criminals’ code of honour.”"

2. (rare) A cooperator.Examples: "Succeſſe vnto our valiant Generall, / And happineſſe to his accomplices."rare