Meaning

originA clipped form of English cant dunnakin (“outhouse”) + -y (suffix forming affectionate diminutives). Dunnakin, dunnekin, etc. are of uncertain etymology, but probably from some form of English cant danna (“dung”) + ken (“house”, pejorative slang). The Scottish and North English senses may derive from Etymology 4 below, either under influence from English cant or as its original source.

Etymology from Wiktionary, CC BY-SA 3.0