Definition of "plumptitude"

His own sister is happy to oblige his fondness for rich fare and both are cushion-rump'd, with Mr. Butterwerthe's posterior greatly resembling that of his own sister's in its plumptitude.

2004, Pamala-Suzette Deane, My Story Being this: Details of the Life of Mary Williams Magahee, Lady of ...‎

At the close of the second act the Viennese dancers tripped upon the stage. These, as you know, are twenty or thirty children, apparently from five years old to to ten, who dress and dance like full-grown dancing girls, and produce astonishing effects by their well-drilled combinations. They are curiosities, if it were only for the robust development of their little bodies. Seen through a magnifying glass, their short petticoats, etc., would hardly look decent; but, as children, the plumptitudes which they expose by every movement are humorously beautiful.

1845 August 2, N[athaniel] P[arker] W[illis], “Number Three. […]”, in United States Saturday Post, volume XXVI, number 1253, Philadelphia, Pa., page , column 1

Excuse, therefore, the shortcomings of genius under the soporific influence of the summer solstice; for, be assured that a vertical sun, however it may dulcify and mature cherries, plums, and other fruital “plumptitudes,” is by no means favorable to the development of intellectual products.

1854 January, “A New York Editor”, quotee, “Mirror of Apothegm, Wit, Repartee, and Anecdote”, in The Ladies’ Repository, volume XIV, number 1, page 45, column 1

An old Indian “Howed” to all who passed, and looking at the expanded crinoline of the ladies, exclaimed, “Heap wigwam,” while his squaw looked on stolidly till President Pomeroy seized her young papoose, and bore it, squalling and kicking, towards the train. Its wrinkled face might readily have been taken for the spanked plumptitudes of a more favorably born infant, while all were favored with cumulative evidence of the strength of lungs inherited by a juvenile Indian.

1867, “Grand Excursion.—Central Branch Union Pacific Railroad.—Speeches of Distinguished Visitors.—A Gala-Day.”, in Excursion of the Directors and Stockholders of the Central Branch, Union Pacific Railroad. November, 1866., New York, N.Y.: The New York Printing Company, […], page 91