The prefix "cis-" (as in "cissexual" or "cisgender") is complementary to the prefix "trans-" (as in "transsexual", "transvestite," "transgender", etc.) So, people who are not transgender are cisgender while people who are not transsexual would be cissexual, people who are not transvestite would be cisvestite.

Typically, a cissexual or cisgender person is one who is comfortable in the sex/gender he or she was assigned at birth. A cisvestite would wear the clothing expected of their birth sex.