definition of
drop-off

[1] #1 drop-off n. [slump, slack, falloff, falling off] 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". wn

[2] #2 drop-off n. [cliff, drop] a steep high face of rock; "he stood on a high cliff overlooking the town"; "a steep drop". wn

[3] #3 drop-off n. [decrease, lessening] a change downward; "there was a decrease in his temperature as the fever subsided"; "there was a sharp drop-off in sales". wn