What does it mean?
“Bock zu haben” basically means to want to do something (although it literally means to have a male mammal). The equally popular phrase “kein Bock zu haben” means to not want to do something.
The word “Bock”, however, directly translates into buck, meaning a male mammal. It is also short for Ziegenbock, which means ram. This can confuse natives as well as newcomers to the German language as to how the phrase was born.
What are its origins?
The word Bock traces back to the Romani word bokh, which means hunger. This coincides with its use today, as “Bock zu haben” therefore technically means “to have hunger for something”.
The word was absorbed as Bock into Rotwelsh (meaning argot), which was a group of secret languages for criminals and gypsies in the late Medieval Times. It was later absorbed into German to mean a male mammal as well as a ram. Perhaps because male mammals ate a lot and were therefore seen as hunger incarnates?
The phrase “Bock zu haben” emerged in 70s Jugendsprache (meaning “youth-language”, which is basically youth slang); however the direct link between this and Rotwelsh is difficult to imagine. However the phrase “geiler Bock” (meaning a lustful man) was known well before then, so “Bock zu haben” most likely came directly from there.
How is it used?
“Bock zu haben” is perhaps one of the most widely used phrases of Umgangssprache (literally meaning “handling-language”, but actually meaning “street talk”). Since its 70s origins, it has still remained more popular with the German youth. It is often paired with the German “Null” (meaning zero), so someone might have “Null Bock” (zero ambition to do something.
Uses of 'Bock haben':
Willst du morgen zum Kino gehen?
“Ne, hab kein Bock.”
Want to go to the cinema tomorrow?
“No, I don’t feel like it.”
Ich hab echt Bock ein Film zu gucken.
I really want to watch a film.
Boah, jetzt hab ich null Bock auf noch ne’ scheiß Klassenarbeit bei dieser Hitze zu schreiben.
I have zero ambition to do another damn test in this heat.