Definition of "knocking"

knocking

/ˈnɑkɪŋ/

verb
1. present participle and gerund of knock
noun
plural knockings
1. An act in which something is knocked on, or the sound thus produced
  Quotations
  These strange openings and closings and knockings were warnings and reminders from the spirits who attend the dying.
  1893, W. B. Yeats, The Celtic Twilight‎
  There was no response to continued knockings.
  1901, Carson Jay Lee, Oswald Langdon‎
  Recorded live to CD with new instrumentation--artillery shells, tuned suspension cables, boxes filled with springs--and deemphasized guitar parts, it's a beautiful collection of echoes and whispers, drones and knockings, with a gently swelling sense of the sinister.
  2006 July 21, Keith Harris, Monica Kendrick, Peter Margasak, Bob Mehr, Miles Raymer, Neil Tesser, “The Treatment”, in Chicago Reader‎
2. (automotive) A repetitive ping, knock, or similar sound coming from an engine in which there are repeated uncontrolled explosions in the combustion chamber.
  Quotations
  Knocking can also occur at high speed, but that may go undetected by the driver.
  2021 December, The Road Ahead, Brisbane, page 56, column 1