A partnership between two people. This partnership is not a relationship, but is more than fuck buddies. For one reason one or both partners do not want a relationship but don't want their partner to be seeing anyone else.
Like minded person: Are you dating Chris?
Exclusiveship partner: No we are not dating, we are in an exclusiveship.
Like minded person: What's an exclusiveship?
Exclusiveship partner: IDK man, we hang out.
Like minded person: Is he/she your bf/gf?
Exclusiveship partner: No...
Like minded person: Are you just fuck buddies?
Exclusiveship partner: No...
Like minded person: Well what the hell is it?
Exclusiveship partner: IDK...