flop

1. VERB

If you flop into a chair, for example, you sit down suddenly and heavily because you are so tired.

• Bunbury flopped down upon the bed and rested his tired feet.     
• She flopped, exhausted, on to a sofa.     
• = collapse   

2. VERB

If something flops onto something else, it falls there heavily or untidily.    

• The briefcase flopped onto the desk.     
• His hair flopped over his left eye.

3. N-COUNT : oft adj N

If something is a flop, it is completely unsuccessful.[ INFORMAL ]    

• It is the public who decide whether a film is a hit or a flop.     
• = failure   

4. VERB

If something flops, it is completely unsuccessful.[ INFORMAL ]    

• The film flopped badly at the box office.
  

.... Cobuild