proprietarial

Perhaps proprietary +‎ -al influenced by proprietorial, or perhaps a variant of the latter influenced by the former.

proprietarial

1. Pertaining to proprietarians or proprietarianism (in colonial North America).
   • 2015, Timothy Paul Grady, Anglo-Spanish Rivalry in Colonial South-East America, 1650–1725, Routledge, →ISBN, page 140:

     In Charleston, the aftermath of the Yamassee War was one of reorganization, regulation and a massive political shift as the colony moved from proprietarial control to become a royal colony.

2. (uncommon) Proprietary or proprietorial; pertaining to property or ownership (of property).
   • 2008, Enrico Dal Lago, Constantina Katsari, Slave Systems: Ancient and Modern, Cambridge University Press, →ISBN, page 76:

     They extended the proprietarial and contractual provisions of emerging commercial law to seize local peasant debtors as slaves, [...] ‘Proprietarial’ interests in both outsiders and local debtors, commercialized for purposes of negotiability, thus appeared several millennia ago in Mesopotamia. However, to construe these atypical transactions [...] as defining of ‘slavery’, would then indulge the selective fallacy of origins — in relation to modern thoroughly proprietarial slavery [...]

• proprietarian
• proprietarianism
• proprietorial