Scupper

Scupper is a term with nautical and architectural meanings, referring to openings or channels that drain water, as well as a verb used figuratively to mean thwart or ruin. In ships and boats, a scupper is an opening in the deck or side that allows water—such as rain or wash from the deck—to drain overboard. Scuppers are typically fitted with gratings or plates and connected to drainage channels or trunks that carry water away from the deck and over the hull or gunwale. They are commonly located on exposed decks to prevent water accumulation and maintain stability, with design and placement varying by vessel type and climate.

In architecture and civil engineering, a scupper is a drainage opening or channel built into a parapet, terrace, or roof edge to discharge water away from the surface and walls. Scuppers may be rectangular or circular and are often protected by grills or screens to prevent debris entry while allowing water to escape. They connect to internal downspouts, drainage pipes, or external channels and are used on flat roofs, courtyards, and similar areas to avoid ponding and related damage.

As a verb, scupper means to ruin, derail, or sink a project or plan. In nautical usage, to scupper can also imply opening a drain to relieve flooding, effectively permitting water to escape from a space.

The term originated in nautical contexts and was later extended to architectural drainage and figurative use.