1. obstacle race a race in which competitors must negotiate obstacles
  2. abstract existing only in the mind
  3. obstreperous noisily and stubbornly defiant
  4. obstacle something that stands in the way and must be surmounted
  5. obstetrics the branch of medicine dealing with childbirth and care of the mother
  6. osteoclasis treatment of a skeletal deformity by intentionally fracturing a bone
  7. bicycle race a race between people riding bicycles
  8. obstinate marked by tenacious unwillingness to yield
  9. abstruse difficult to understand
  10. obstreperousness noisy defiance
  11. obstetrician a physician specializing in childbirth
  12. abstinence the trait of refraining from something, especially alcohol
  13. stake race a horse race in which part of the prize is put up by the owners of the horses in the race
  14. spastic paralysis a loss or deficiency of motor control with involuntary spasms caused by permanent brain damage present at birth
  15. obstreperously in manner that attracts attention
  16. obstetrical of or relating to or used in or practicing obstetrics
  17. epistaxis bleeding from the nose
  18. abstruseness the quality of being unclear or abstruse and hard to understand
  19. obstetric of or relating to or used in or practicing obstetrics
  20. abstractedness preoccupation with something to the exclusion of all else