adj.
  - in a very poor condition as a result of disuse and neglect.
 - chiefly N. Amer. shamefully negligent.
 
n.
  - a destitute person.
 - a ship or other piece of property abandoned by its owner.
 
 
  Etymology
  C17: from L. derelict-, derelinquere ‘abandon’, from de- ‘completely’ + relinquere ‘forsake’.