1. ambiguous having more than one possible meaning
  2. impenetrable not admitting of passage into or through
  3. imponderable difficult or impossible to evaluate with precision
  4. ambitious having a strong desire for success or achievement
  5. combinatorial relating to or involving combinations
  6. ambient completely enveloping
  7. ambiguity unclearness by virtue of having more than one meaning
  8. imminent abortion the appearance of symptoms that signal the impending loss of the products of conception
  9. ambience the atmosphere of an environment
  10. ambivalence mixed feelings or emotions
  11. Ambrose Bierce United States writer of caustic wit (1842-1914)
  12. American parasol an agaric with a pallid cap and a stalk that is enlarged near the base
  13. ambrosial worthy of the gods
  14. ambivalent uncertain or unable to decide about what course to follow
  15. antiparallel (especially of vectors) parallel but oppositely directed
  16. ambiance the atmosphere of an environment
  17. ambitiously with ambition; in an ambitious and energetic manner
  18. impenitence the trait of refusing to repent
  19. combined operation a military operation carried out cooperatively by two or more allied nations or a military operation carried out by coordination of sea, land, and air forces
  20. impendence the state of being imminent and liable to happen soon