From dun + -y.

• IPA: /dʌni/

dunny (comparative dunnier, superlative dunniest)

1. Somewhat dun, dusky brownish.
   • c. 1517 (date written; published c. 1545), John Skelton, “Here after Foloweth the Booke Called Elynour Rummynge. The Tunnyng of Elynour Rummyng per Skelton Laureat.”, in Alexander Dyce, editor, The Poetical Works of John Skelton: […], volume I, London: Thomas Rodd, […], published 1843, →OCLC ↗, page 108 ↗, lines 399–400:

     I were skynnes of conny, / That causeth I loke so donny.

     I wear skins of cony [rabbit], / That cause me to look so dunny.

Probably from dun + -y.

dunny (comparative dunnier, superlative dunniest)

1. (UK dialect) Somewhat deaf, hard of hearing.
   • 1708, J. Kersey, Dictionary Anglo-Britannicum:

     Dunny, somewhat deaf, deafish.

2. (UK dialect, pejorative, , euphemism) Slow to answer: stupid, unintelligent.
   • a. 1791, F. Grose, Olio, p. 105:

     What the devil are you dunny? won't you give me no answer?

dunny (plural dunnies)

1. (UK dialect, pejorative euphemism, obsolete) A dummy, an unintelligent person.
   • 1709, British Apollo, Vol. II, No. 29, p. 3:

     Should a School-boy do so, he'd be whip'd for a Dunny.

A clipped form of English cant dunnakin ("outhouse") + -y ("forming affectionate diminutives"). Dunnakin, dunnekin, etc. are of uncertain etymology, but probably from some form of English cant danna ("dung") + ken ("pejorative slang for house").

dunny (plural dunnies)

1. (UK slang, obsolete) Alternative form of danna: shit. [From 1859.]
2. (Australia & New Zealand slang, also dated Scotland & North England slang) An outhouse: an outbuilding used as a lavatory. [From 1933.]
   • 2008, Judith L. McNeil, No One's Child‎, page 95:

     There was one leaning dunny down the back and, if you stayed very quiet, on a very still day you could hear the white ants as they chewed the wood.The bottom boards were already eaten through, and I avoided using the dunny at all costs.

3. (Australia & New Zealand slang) Any other place or fixture used for urination and defecation: a latrine; a lavatory; a toilet.
   • 2010, Kathleen M. McGinley, Out of the Daydream‎, page 47:

     The dunny was another place to go to get out of class. You got to go there by raising your hand in class and asking Miss if you could go to the lav.

4. (Scottish, northern England, slang, dated) A passageway, particularly those connecting an outhouse to the main building.

• (outhouse) See Thesaurus:bathroom
• (toilet) See Thesaurus:toilet

A clipped form of English dungeon + -y.

dunny (plural dunnies)

1. (Scottish, northern England, slang, dated) A cellar, basement, or underground passage.