1. insulin hormone secreted by the isles of Langerhans in the pancreas
  2. insolent marked by casual disrespect
  3. insomnia an inability to sleep
  4. insulant a material that reduces or prevents the transmission of heat or sound or electricity
  5. insolence the trait of being rude and impertinent
  6. insular relating to or characteristic of or situated on an island
  7. inulin used to manufacture fructose and in assessing kidney function
  8. insidious working or spreading in a hidden and usually injurious way
  9. insignia a badge worn to show official position
  10. incline lower or bend, as in a nod or bow
  11. insulate surround with material to protect from heat, cold, or noise
  12. insulting expressing extreme contempt
  13. insulation reduction of the transmission of sound, heat, or electricity
  14. insult treat, mention, or speak to rudely
  15. insane afflicted with or characteristic of mental derangement
  16. in line awaiting something; especially something due
  17. unsullied free from blemishes
  18. ensure make certain of
  19. ancillary furnishing added support
  20. insolation incident solar radiation