drop-off

noun

1. 1

   a change downward

   there was a decrease in his temperature as the fever subsided

   there was a sharp drop-off in sales

2. 2

   a steep high face of rock

   he stood on a high cliff overlooking the town

   a steep drop

3. 3

   a noticeable deterioration in performance or quality

   the team went into a slump

   a gradual slack in output