Other forms: flopped, flops, flopping
A flop is something that fails completely and in public: a film nobody goes to see, a product pulled from the shelves after three months. The word carries the sound of it, flat and heavy and over.
The verb is the one you use every day, and it has nothing to do with failing — you flop into an armchair at the end of a long day, hair flops over your eyes, a fish flops about on the deck. Then the other verb: the show flopped, the launch flopped. Flop is blunt and informal, a word for a friend rather than for a serious review. Around it sit belly flop, flip-flop, and floppy, which is what a spaniel's ears are.
1nounflopA complete public failure, especially of a film, show or product.
“The film was an expensive flop.”
informal in this meaning — an editor’s judgement
2verbfailTo fail badly.
“The play flopped and closed after two weeks.”
informal in this meaning — an editor’s judgement
3verbdropTo drop or fall heavily and loosely.
“He flopped into the armchair without taking his coat off.”
flop is a failure.
Flop has been in print since 1602 and is probably just flap with a duller, heavier vowel: flap is quick and light, flop lands. English kept both, which is why a person can flop into a chair and a film can flop at the box office.
Recorded since 1602, probably a variant of flap with a duller, heavier sound.
Etymology from Wiktionary, CC BY-SA