(Scotland, obsolete) Used by people in medieval Scotland to warn passers-by of waste about to be thrown from a window into the street below. The term was still in use as late as the 1930s and 1940s, when many people had no indoor toilets.

(Scotland, historical) A cry of "gardyloo". / An act of discarding waste or some other substance from a height. Also attributive and figurative. / (figuratively) Caution, warning.

plural of gardyloo