flop

[1]	collapse , drop (down) , fall (down) , tumble , topple , plump down , plop down , flounce down
[2]	flap , wave , swing
[3]	fail , fall flat , come to naught/nothing , founder , (Colloq) fold , (US) bomb
[4]	fall through , fall flat , founder

[1]	floating-point operation
[2]	dud , washout
[3]	bust , fizzle
[4]	collapse , failure , fiasco , disaster , non-starter , debacle , (US) fizzle , (Colloq) dud , washout , clanger , (US) lead balloon , bomb , (Slang) lemon , (Brit) cock-up , damp squib

adv.

[1]

right