flop

nouns

an arithmetic operation performed on floating-point numbers
"this computer can perform a million flops per second"
someone who is unsuccessful
a complete failure
"the play was a dismal flop"
the act of throwing yourself down
"he landed on the bed with a great flop"
is derived from

verbs

fall loosely
"He flopped into a chair"
is a type of (narrower)
break down, literally or metaphorically
"The wall collapsed"; "The business collapsed"; "The dam broke"; "The roof collapsed"; "The wall gave in"; "The roof finally gave under the weight of the ice"
fall suddenly and abruptly
is a type of (narrower)
move downward and lower, but not necessarily all the way
"The temperature is going down"; "The barometer is falling"; "The curtain fell on the diva"; "Her hand went up and then fell again"
fail utterly; collapse
"The project foundered"

adverbs

with a flopping sound
"he tumbled flop into the mud"
exactly
"he fell flop on his face"