1. detector a device that receives a signal and responds to it
  2. didactic instructive, especially excessively
  3. defector a person who abandons their duty, country, or cause
  4. detect discover or determine the existence, presence, or fact of
  5. detected perceived or discerned
  6. detractor one who disparages or belittles the worth of something
  7. detective a police officer who investigates crimes
  8. director someone who manages an organization
  9. character a property that defines the individual nature of something
  10. directory an alphabetical list of names and contact information
  11. lie detector a polygraph that records bodily changes sometimes associated with lying
  12. detached no longer connected or joined
  13. detonator a mechanical or electrical explosive device or a small amount of explosive; can be used to initiate the reaction of a disrupting explosive
  14. dedicated devoted to a cause or ideal or purpose
  15. dictator a ruler who is unconstrained by law
  16. deduct make a subtraction
  17. redactor someone who puts text into appropriate form for publication
  18. detectable capable of being discovered
  19. deductive relating to reasoning from the general to the particular
  20. deter turn away from by persuasion