1. slacken off become less intense
  2. slackness the quality of being loose (not taut)
  3. slickness a slippery smoothness
  4. slack off become less in amount or intensity
  5. sleekness the smooth feel of silk fabric
  6. slackening an occurrence of control or strength weakening
  7. slacken become slow or slower
  8. slacking the evasion of work or duty
  9. blackness total absence of light
  10. slack suit casual dress consisting of slacks and matching jacket
  11. slacks (usually in the plural) pants for casual wear
  12. sulkiness a mood or display of sullen aloofness or withdrawal
  13. silkiness the smooth feel of silk fabric
  14. glockenspiel a percussion instrument consisting of a set of metal bars
  15. eloquence powerful and effective language
  16. blacken out darken completely
  17. bleakness a bleak and desolate atmosphere
  18. silicone resin a polymeric silicone compound
  19. pluckiness the trait of showing courage and determination in spite of possible loss or injury
  20. flakiness having or breaking into thin crisp flakes