drop-off
     n 1: a noticeable deterioration in performance or quality; "the
          team went into a slump"; "a gradual slack in output"; "a
          drop-off in attendance"; "a falloff in quality" [syn: {slump},
           {slack}, {falloff}, {falling off}]
     2: a steep high face of rock; "he stood on a high cliff
        overlooking the town"; "a steep drop" [syn: {cliff}, {drop}]
     3: a change downward; "there was a decrease in his temperature
        as the fever subsided"; "there was a sharp drop-off in
        sales" [syn: {decrease}, {lessening}] [ant: {increase}]
Source: WordNet® 2.0