kerplunk

From ker- +‎ plunk.

kerplunk (plural kerplunks)

1. A thudding or thunking sound.
   • 2007, Michelle Tea, Rose of No Man's Land

     If my life were a Saturday-morning cartoon, you would have heard a loud kerplunk as my stomach dropped. My poor starving stomach.

kerplunk

1. A thudding or thunking sound.
   • 1986, Eva Bunting, Sixth-Grade Sleepover

     I called the number out loud for her, and inside me my heart was suddenly going "kerplunk, kerplunk, kerplunk," heavy as an elephant's feet.

kerplunk (third-person singular simple present kerplunks, present participle kerplunking, simple past and past participle kerplunked)

1. To make a thudding or thunking sound.