intransitive verb
Definition: To fall or drop heavily, often making a soft thudding sound.
Example: After a long day, he flumped onto the couch and sighed.
noun
Definition: A low, heavy sound made when something falls or drops onto a surface.
Example: The book fell off the shelf with a loud flump.
transitive verb
Definition: To drop or place something in a heavy or clumsy way, often making a sound.
Example: He flumped the bag onto the floor with a loud thud.