# upper decker

> English word · Noun

## Definitions
1. The prank of defecating in the cistern of a toilet, so that flushing the toilet brings in dirty water instead of clean.

## Etymology
From upper + deck + -er.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/upper-decker