1. improper fraction a fraction whose numerator is larger than the denominator
  2. proper fraction a fraction with a numerator smaller than the denominator
  3. imperfection the state or an instance of being flawed
  4. appropriation a deliberate act of acquisition, often without permission
  5. improvisation a performance given without planning or preparation
  6. simple fraction the quotient of two integers
  7. imprecation the act of calling down a curse that invokes evil
  8. compound fraction a fraction with fractions in the numerator or denominator
  9. complex fraction a fraction with fractions in the numerator or denominator
  10. double refraction splitting a ray into two parallel rays polarized perpendicularly
  11. appropriate suitable for a particular person, place, or situation
  12. impossible action an alternative that is not available
  13. angle of refraction the angle between a refracted ray and a line perpendicular to the surface between the two media at the point of refraction
  14. index of refraction the ratio of the velocity of light in a vacuum to that in a medium
  15. proportion relation with respect to comparative quantity or magnitude
  16. prevarication the deliberate act of deviating from the truth
  17. refraction the change in direction of a propagating wave
  18. expropriation taking out of an owner's hands
  19. infraction a violation of a law or rule
  20. impersonation pretending to be someone else