Definition & Meaning of "through the roof"in English

What does "through the roof" mean in slang?

The phrase "through the roof" means something is extremely high, especially in degree, intensity, or quantity. The structure comes from the literal idea of something rising beyond a building's roof, used metaphorically to describe sharp increases or extreme levels. It is informal slang commonly used for prices, emotions, or performance levels, such as "prices went through the roof" or "his excitement went through the roof."