1.Definition: (of persons) taken advantage of
"After going out of his way to help his friend get the job he felt not appreciated but used"
Related Adjective(s):exploited, victimised, victimized
2.Definition: employed in accomplishing something
"The principle of surprise is the most used and misused of all the principles of war"
3.Definition: previously used or owned by another
"Bought a secondhand (or used) car"