Definition of downhill adverb from the Oxford Advanced Learner's Dictionary

  • BrE BrE//ˌdaʊnˈhɪl//
    ; NAmE NAmE//ˌdaʊnˈhɪl//
    towards the bottom of a hill; in a direction that goes down to run/walk/cycle downhill opposite uphill See related entries: Mountains and valleys
  • Idioms to get worse in quality, health, etc. synonym deteriorate Their marriage went downhill after the first child was born. He’s been going slowly downhill since he came out of hospital.
    See the Oxford Advanced American Dictionary entry: downhill