plonk1

verb

• 1 [with object and adverbial of place] set down heavily or carelessly:she plonked her glass on the table
• (plonk oneself) sit down heavily and without ceremony:he plonked himself down on the sofa

• 2 [no object] play unskilfully on a musical instrument:people plonking around on expensive instruments

noun

• a sound as of something being set down heavily:he sat down with a plonk