Nouns

(n)plonka cheap wine of inferior quality
(n)plonkthe noise of something dropping (as into liquid)

Verbs

(v)plank, flump, plonk, plop, plunk, plump down, plunk down, plumpset (something or oneself) down with or as if with a noise“He planked the money on the table”, “He planked himself into the sofa”