The word "slovenly", meaning "untidy or careless", derives from the 15th-century word "sloven" which meant "a rascal" or "a person with horrible manners", and that possibly stems from either Flemish "sloef" (dirty) or Dutch "slof" (careless or negligent).  

The earliest known use of "slovenly" in English, both as an adjective and an adverb, appears around the mid-1500s, with the Oxford English Dictionary (OED) citing evidence from 1518 for the adjective and 1548 for the adverb. 

Examples of slovenly in a sentence: 
He dressed in a slovenly manner, with his clothes rumpled and his hair unkempt. 
The slovenly habits of the campers left the campsite littered with trash and debris. 
Her slovenly appearance made her seem unkempt and unkempt. 
The slovenly work habits of the employees resulted in numerous errors and delays. 
The slovenly condition of the house made it difficult to find anything. 
There's no defense for the slovenly ethics of the past. 
Be a little slovenly in the garden; leave some old broken stems and let a little bare dirt show.
That's what infused his slovenly pirate thing with such style. 

Just the facts:

SLOVENLY Definition & Meaning - Merriam-Webster

OMG @Myr have you installed surveillance cameras! Slovenly is how my house looks before I know I'll have visitors.