bekloppt
crazy / stupid
A colloquial, often derogatory expression for crazy, stupid, or nonsensical.
Er hat die bekloppte Idee, im Winter im See zu baden.
He has the crazy idea of swimming in the lake in winter.

crazy / stupid
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crazy / stupid
A colloquial, often derogatory expression for crazy, stupid, or nonsensical.
Er hat die bekloppte Idee, im Winter im See zu baden.
He has the crazy idea of swimming in the lake in winter.

'Bekloppt' (crazy/stupid) is a very informal colloquial word. It can be perceived as insulting and should therefore be avoided in formal or polite conversations.
Halt mich nicht für bekloppt, aber ich glaube, ich habe ein Gespenst gesehen.
Don't think I'm crazy, but I think I saw a ghost.
The word is figuratively derived from 'klopfen' (to knock). The idea is that someone has been knocked on the head so often that he or she can no longer think clearly.
Was für eine bekloppte Regelung, die versteht doch niemand!
What a stupid rule; nobody understands it!
The adjective 'bekloppt' (crazy/stupid) can describe both people and ideas, plans, or actions that one considers crazy or stupid.
Mein Nachbar ist total bekloppt, er mäht nachts den Rasen.
My neighbor is totally crazy; he mows the lawn at night.
stupid / unfortunate
'dumm' and 'bekloppt' can both express that something is not smart or is nonsensical. 'dumm' is more general and can sound a bit more matter-of-fact, even though it is negative. 'bekloppt' is very colloquial and often stronger. It can also mean 'crazy', not just 'not very intelligent'. Learners may confuse the words because both can be said about stupid ideas or behavior. In normal or formal situations, 'dumm' is safer; 'bekloppt' fits better among friends and can come across as insulting.

Sie findet es bekloppt, mitten in der Nacht noch einkaufen zu gehen.
She thinks it's crazy to go shopping in the middle of the night.
Vor dem Termin war es dumm, die wichtigen Unterlagen zu Hause zu lassen.
Before the appointment, it was stupid to leave the important documents at home.