A more thorough explanation:

A subpartnership is a type of partnership where a nonpartner shares the profits and losses of a firm's business with a partner, but without forming a legal partnership between them. It is an arrangement between a partner and a nonpartner.

For example, if a partner in a law firm brings in a client and shares the profits with a nonpartner who helped with the case, it would be considered a subpartnership. The nonpartner is not officially part of the law firm, but they are sharing in the profits of a specific case.

This type of partnership is different from a general partnership or a limited partnership, where all partners are legally bound to each other and share in the profits and losses of the entire business.