Not identical; different in some respect.

A twin other than an identical twin.

In a nonidentical manner; differently.

plural of nonidentical

plural of nonidentity

Difference, distinction; failure to be identical. / (mathematics) An operator which modifies its operand, and which therefore is not the identity.

(philosophy) the philosophical problem involving our ethical obligations to future persons which derives from the observation that different courses of action will result in entirely different, or nonidentical, persons coming to be.