Definitions

1. verb

to fall or drop suddenly, especially with a loud noise

“The ball kerplunked to the floor, shattering into pieces.”

2. noun

a sudden falling or dropping of something, often with a loud noise

“The kerplunk of the book hitting the floor startled the cat.”

3. interjection

used to express the sound of something falling or dropping

“Kerplunk! The book fell to the floor.”