What is At Arm's Length?

Legal Definition
Beyond the reach of personal influence or control. Parties are said to deni "at arm's length" when each stands upon the strict letter of his rights, and conducts the business in a formal maimer, without trusting to the other's fairness or integrity, and without being subject to the other's control or overmastering influence.
-- Black's Law Dictionary
Legal Definition
Without another’s influence.
-- Ballentine's Law Dictionary