1. doubtlessly without doubt; certainly
  2. subtle difficult to detect or grasp by the mind or analyze
  3. double salt a solution of two simple salts that forms a single substance on crystallization
  4. doubtless certainly; without question
  5. dauntlessly without fear
  6. ductless gland any of the glands of the endocrine system that secrete hormones directly into the bloodstream
  7. double feature two games instead of one
  8. Digitalis lutea European yellow-flowered foxglove
  9. doubtful fraught with uncertainty
  10. thoughtlessly in a thoughtless manner
  11. doubtfully in a doubtful manner
  12. tactlessly without tact; in a tactless manner
  13. Hubble's law (astronomy) the generalization that the speed of recession of distant galaxies (the red shift) is proportional to their distance from the observer
  14. capital of Italy capital and largest city of Italy
  15. spotlessly in a spotless manner
  16. double talk deliberately unintelligible gibberish
  17. catalyst substance that initiates or accelerates a chemical reaction
  18. capitalism an economic system based on private ownership of assets
  19. copper sulfate a copper salt made by the action of sulfuric acid on copper oxide
  20. sodium sulfate a solid white bitter salt used in manufacturing glass and paper and dyes and pharmaceuticals