A fork of Rural Dictionary
Bumbklaatt is a Portuguese term. It is the strongest insult in the language. Similar to Mother F*cker in the English language.
If you are looking this word up, you probably heard it from the band Soulfly. It is the name of one of their songs and is frequently used in their lyrics.
From Soulfly - Bumbklaatt:
You fake
You waste
You bumbklaatt...