usage: 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"
Verb
1. fall off, detach, come off, come away
usage: come off; "This button had fallen off"
2. slump, fall off, sink, drop
usage: fall heavily or suddenly; decline markedly; "The real estate market fell off"
3. fall off, fall away, disappear, vanish, go away