If the question pertains to the relationship among the persons involved, arm's length seems to be the legal term in use in North America.

From Canada Revenue Agency:
The term “at arm's length” describes a relationship where persons act independently of each other or who are not related. The term “not at arm's length” means persons acting in concert without separate interests or who are related.

From Wikipedia: The arm's length principle (ALP) is the condition or the fact that the parties to a transaction are independent and on an equal footing. Such a transaction is known as an "arm's-length transaction". It is used specifically in contract law to arrange an equitable agreement that will stand up to legal scrutiny, even though the parties may have shared interests (e.g., employer-employee) or are too closely related to be seen as completely independent (e.g., the parties have familial ties).