What is the meaning of thudding?

verb

• Make a dull sound.
  • usage: "the knocker thudded against the front door"
  • synonyms: thud, thump
• Strike with a dull sound.
  • usage: "Bullets were thudding against the wall"
  • synonyms: thud
• Make a noise typical of an engine lacking lubricants.
  • synonyms: crump, thud, scrunch

adjective

• Not clear and resonant; sounding as if striking with or against something relatively soft.
  • usage: "the dull thud"; "thudding bullets"
  • synonyms: dull