According to the celebrated poet by this name, Martin Farquhar Tupper, it is a corruption of part of the motto of the family, "Tout perdie."

Arthur, William (1857) An Etymological Dictionary of Family and Christian Names. New York: Sheldon, Blakeman. Public Domain.

TUPPER. Appears in its original form as Toppfer — a name well-known in the literature of Germany and Frauce. The family, widely scattered in the religious troubles of the XVI. cent., having "lost all " under Charles V., as obstinate Lutherans, were called Tout-perd in France, and, by corruption, Toupard in the Netherlands ; while in Guernsey aud England, and among the Puritan fathers of America, the name assumed the form so familiar to the public as the designation of the author of" Proverbial Philosophy." The principal branch went to Guernsey in 154:8.

Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.