The word "disheveled" comes from the Old French verb descheveler, meaning "to disarrange the hair".   It's formed from the prefix des- (meaning "apart" or "away") and the word chevel, meaning "hair" (from the Latin capillus). The original sense in Middle English was "bare-headed" or with disordered hair, with the more general meaning of disordered dress developing later. 

According to the Oxford English Dictionary (OED), the adjective dishevelled was first used in English in the Middle English period, with the earliest evidence for its use dating back to 1493.  The word may have entered English as a partial translation of the Anglo-French word deschevelé in the 14th century. 

Example of "disheveled" used in a sentence:  
"She twirled a strand of her long hair and smirked at my disheveled appearance." 
"He ran a hand through his disheveled hair and cleared his throat, looking faintly embarrassed." 
"In addition, they have a rough coat that gives them a disheveled appearance." 
"His wrinkled suit gave him a disheveled appearance." 
"What's up with the beard, nose ring and disheveled hair?"  
"The glass front door of the business was smashed and a desk was found disheveled." 

Just the facts:

DISHEVELED Definition & Meaning - Merriam-Webster

DISHEVELED Synonyms: 166 Similar and Opposite Words | Merriam-Webster Thesaurus