plunk · noun, adverb, interjection, verb1
Onomatopoeic; the noun is attested earlier than the verb. Noun etymology 1, noun sense 3 (“dollar; large sum of money”) may refer to the sound of a coin hitting a surface. Compare plonk, plink. As regards verb etymology 1, verb sense 1.4 (“(transitive) to drop, set, or throw (something, or oneself) abruptly and/or heavily”) and etymology 1, verb sense 2.4 (“(intransitive) to drop, land, or set abruptly and/or heavily”), compare French plonquer (Picardy), a variant of plonger (“to plunge”).
plunk · verb2
- Dutch · derived fromplenken“(archaic) to wander around; (Limburg, archaic) to play truant”
- English todayplunk
Origin uncertain; possibly the same as plunk (etymology 1), or related to Dutch plenken (“(archaic) to wander around; (Limburg, archaic) to play truant”).
Etymology from Wiktionary, CC BY-SA 4.0.