Adjective

(en adjective)

Appropriate to or characteristic of a slattern.

*1886 , (Robert Louis Stevenson), (Strange Case Of Dr Jekyll And Mr Hyde)

*:The dismal quarter of Soho seen under these changing glimpses, with its muddy ways, and slatternly passengers, and its lamps, which had never been extinguished or had been kindled afresh to combat this mournful reinvasion of darkness, seemed, in the lawyer's eyes, like a district of some city in a nightmare.

Adjective

(er)

In a disorderly state; chaotic; disorderly.

*{{quote-magazine, date=2013-08-03, volume=408, issue=8847, magazine=(The Economist)

, title= Boundary problems , passage=Economics is a messy discipline: too fluid to be a science, too rigorous to be an art. Perhaps it is fitting that economists’ most-used metric, gross domestic product (GDP), is a tangle too. GDP measures the total value of output in an economic territory.}}

(of a person) Prone to causing mess.

(of a situation) Difficult or unpleasant to deal with.