c. 1500, from adjectival use of past participle of wear (v.); from Old English geworen. Worn-out "exhausted by wear, made ineffective by overuse" is attested from 1610s in reference to things, c. 1700 in reference to persons.
worn threads on the screw
a worn suit
the worn pockets on the jacket
worldwide
World-Wide Web
worm
wormhole
wormwood
worn
worrisome
worry
worry wart
worse
worsen