I. verb
1.
Synonyms: fall 2, drop, go down, keel (over), pitch, plunge, topple, tumble
Related Word: droop, flag, sag
Idioms: come down like a rock ( or a ton of bricks)
2.
Synonyms: slouch , droop, loll, ||lollop, lop, trollop
Related Word: cave in, collapse
3.
Synonyms: slip 6, drop (off), fall (off or away), sag, slide
II. noun
1.
Synonyms: decline 3, dip, downslide, downswing, downtrend, downturn, drop, falloff, sag, slip
2.
Synonyms: depression 3, recession, stagnation