used in WordNet English dictionary

1. of persons; taken advantage of
   "after going out of his way to help his friend get the job he felt not appreciated but used"
   exploited  ill-used  put-upon  used  victimized  victimised 
   
2. previously used or owned by another
   "bought a secondhand (or used) car"
   secondhand  used 
   
3. employed in accomplishing something
   "the principle of surprise is the most used and misused of all the principles of war"- H.H.Arnold & I.C.Eaker
   used