ボカッ

adverb, adverb taking the 'to' particle

bop; pow; bonk; thump

Onomatopoeia for a dull impact sound, like a punch or a heavy object hitting something. Often used with と.

• 彼かれはボカッと殴なぐられた。

  He was punched with a thump.

• ボカッという音おとがした。

  There was a bonk sound.