The abrupt sound of two hard objects coming into contact.
Our milkman is a jovial character, but not one given to yodelling at the customers on his round. Only the resounding "clonk" of bottles advises us that a couple of pints have been left on the doorstep.1959 March, R. C. Riley, “Home with the Milk”, in Trains Illustrated, page 154:
He passed under a low branch now. It hit the top of his helmet with a clonk.1969, Kurt Vonnegut, chapter 2, in Slaughterhouse-Five, New York: Dial, published 2005, page 54:
1 more example
The minute hand moved with a clonk, and shuddered to a halt on the 9.2002, Terry Pratchett, Reaper Man:
2
Fishing, Hobbies, Lifestyle A stick-like tool used to strike the surface of the water and produce a sound that causes nearby fish to attack the bait.
clonk
verb
Etymology Imitative. Compare clink, clank, clunk.
1
To make such a sound.
One half-naked kid with a garrison cap clonked on the marimba; the little black rubber balls on his sticks struck fast.1953 September 18, Saul Bellow, chapter XVII, in The Adventures of Augie March […], New York, N.Y.: The Viking Press, →OCLC, page 371: