1. insidious working or spreading in a hidden and usually injurious way
  2. antithesis exact opposite
  3. institution a custom that has been an important feature of some group
  4. institute set up or lay the groundwork for
  5. unstudious not studious
  6. instantaneous occurring with no delay
  7. unsteadiness the quality of not being steady or securely fixed in place
  8. anesthetize administer a numbing or sleep-inducing drug to someone
  9. instance an item of information that is typical of a class or group
  10. institutional relating to an organization founded for a specific purpose
  11. anesthetise administer an anesthetic drug to
  12. constitution the act of forming or establishing something
  13. anastalsis muscular action of the alimentary tract in a direction opposite to peristalsis
  14. constituency the body of voters who elect a representative for their area
  15. institutionalise cause to be admitted; of persons to an institution
  16. unostentatious not ostentatious
  17. anastomosis a natural or surgical joining of parts or branches of tubular structures so as to make or become continuous
  18. insidiousness subtle and cumulative harmfulness (especially of a disease)
  19. incidence the relative frequency of occurrence of something
  20. anesthetist a specialist who administers an anesthetic to a patient before he is treated