contubernal

Living in close proximity (as though sharing a tent); intimate, familiar.

Tributes between poets, chess champions, couturiers—and novelists—are always hopefully contubernal. All such donors really yearn for others to see that the honored one lives in a tent they share.

He was equally joyful when after dinner we heard odd noises, which turned out to be a pair of skuas[…]they were the first living things, other than our contubernial companions, that we had seen in the valley.

Of a relationship between a male and female slave: sexual in nature and somewhat similar to marriage, but not formalized due to the parties being legally unable to marry.

Their contubernal connections are unlimited as to number and local situations, formed and broken off again at pleasure; but the first wife, if still in friendship and confidence of the husband, continues to govern the household, though his appetite may be shared to one, two, or three more.

§ 275. The contract of marriage not being recognized among slaves, of course none of its consequences follow from the contubernial state existing between them.[…]As the fact of cohabiting, and living together as man and wife, is universal among slaves, and the privileges of parents over children, in correcting and controlling them, are universally acceded to them, in all trials of slaves for offences committed by them, these relations are recognized by the Courts[…] § 276. How far this contubernial relation between slaves may be recognized and protected by law, is a question of exceeding nicety and difficulty.