Barnes' partner can be referred to by a variety of synonyms, depending on the context. For example, if they are in a business partnership, they may be called a co-founder, collaborator, or associate. In a marriage or romantic context, they could be known as a spouse, significant other, or life partner. If they work together in a legal or medical profession, they may be called a colleague or co-worker. Other possible synonyms include companion, teammate, ally, mate, or confidant. Ultimately, the specific term used to refer to Barnes' partner will depend on the nature of their relationship and the context in which they are being referred to.