Definition of "plunk"

plunk

/plʌŋk/

verb
third-person singular simple present plunks, present participle plunking, simple past and past participle plunked
1. (transitive) To drop or throw something heavily onto or into something else, so that it makes a dull sound.
2. (intransitive) To land suddenly or heavily; to plump down.
3. (transitive, baseball) To intentionally hit the batter with a pitch.
4. (intransitive, of a raven) To croak.
5. (transitive, music) To pluck and quickly release (a musical string).
  Quotations
  Your bass teacher loathed you for loathing the instrument. Every lesson was the same: You would plunk out a few notes, and he would stop you. “Did you practice ?" “Some," you would say. “You have to practice." “I know." Practicing was the most boring thing you had ever done. Plunk plunk plunk (rest). Plunk plunk plunk (rest). That was pretty much how the double bass part went in every piece of music your teacher assigned you.
  2011, Dave Eggers, Guillermo del Toro, The Best American Nonrequired Reading 2011, Houghton Mifflin Harcourt, page 452
6. (transitive, intransitive, Scotland) To be a truant from (school).
noun
plural plunks
1. The dull thud of something landing on a surface.
2. (slang, obsolete) A large sum of money.
3. (slang, obsolete, US) A dollar.