The word "wiry" is dirived from "wire" and add the suffix "-y", first appearing in the late 1500s to describe things "made of wire" (1580s).  It evolved to describe things "resembling wire" or "in the form of wire"  (like stiff hair) (1590s) and later, a person who is "lean, sinewy, tough, and flexible" (by 1808).  The root word for "wire" traces back to an ancient Proto-Germanic and Proto-Indo-European root meaning "to turn, twist, or plait". 

According to the Oxford English Dictionary (OED), the earliest known use of the adjective wiry is from 1588, in the writing of Thomas Deloney, a silkweaver and writer.  The OED also records a separate, obsolete use of the adjective wiry (adj.²), meaning "of, relating to, or resembling a wire or wire-like thing", with its only evidence dated to 1605 in a translation by Joshua Sylvester. The primary modern sense of the word, as in a person who is thin and strong, is from the 1588 citation. 

Examples of "wiry" used in a sentence: |
"He has dark, wiry hair." 
"Use some conditioner to calm down the wiry hair." 
"Her wiry hair was pushed up on top of her head in an untidy bun." 
"She was lean and wiry from years of working out." 
"Deputies threw the wiry 53-year-old to the floor and handcuffed him." 
"Walt is tall-ish and wiry, with a full beard and a ready smile." 
"The Natal horse is small, wiry, and has great powers of endurance." 
"His body was wiry and lean, his skin golden from sun." 

My body has never been considered wiry, although in the late 70s I was fairly lean.  My mother always claimed I was big-boned.  🤪

Just the facts:

WIRY Definition & Meaning - Merriam-Webster

WIRY Synonyms: 84 Similar and Opposite Words | Merriam-Webster Thesaurus