がたっと

adverb

with a clunk; with a clank

Mimetic word for a heavy, dull impact sound, like something large or solid hitting or falling.

• 棚たなから大おおきな鍋なべががたっと落おちた。

  A big pot fell off the shelf with a clunk.

adverb

sudden drop; sharp decline

Figurative use describing a sudden, noticeable decrease in something like profits, energy, or momentum.

• 今こん月げつの売うり上あげががたっと落おち込こんだ。

  This month's sales suddenly dropped off.