no obj., with adverbial of direction
1- fall or sit down heavily砰地落下（或坐下）：
he took himself off to flump into a chair.
他起身后砰地坐到一把椅子上。
1.1
- with obj. and adverbial of direction set or throw (something) down heavily砰地放下, 砰地扔下：
Ellie flumped her hands down on her sewing.
埃利砰地把双手压在针线活上。
in sing.
- the action or sound of such a heavy fall重落; （下落时）砰的一声：
the rocks hit the ground with a flump.
石头砰地落在地上。
词源
early 17th cent.: imitative.