flop

exactly

“he fell flop on his face”

fail utterly; collapse

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”

an arithmetic operation performed on floating-point numbers

“this computer can perform a million flops per second”

fall loosely

“He flopped into a chair”

fall suddenly and abruptly