Translation of "tapa" into English

Se um estranho me desse um tapa no rosto em plena rua, eu o mataria sem pestanejar.

If a stranger on the street slapped me in the face, I'd kill him without warning.

Bem, mas de bobeira porque as caixas estavam tapando.

That was clumsiness because I was carrying a lot of boxes.

Pessoalmente, acho quase impossível matar com um tapa uma mosca pousada na parede da cozinha.

Personally, I find it almost impossible to swat a large fly that is basking on the kitchen wall.