1. a change downward
e.g. there was a decrease in his temperature as the fever subsided
there was a sharp drop-off in sales
2. a steep high face of rock
e.g. he stood on a high cliff overlooking the town
a steep drop
3. a noticeable deterioration in performance or quality
e.g. the team went into a slump
a gradual slack in output
a drop-off in attendance
a falloff in quality
Synonym: slumpslackfallofffalling off