landslide
n. countablen. a large amount of rocks and earth that suddenly falls down a mountain or hill. It also describes an election victory where one person gets many more votes than their opponent.
n. the rapid downward movement of a mass of rock, earth, or debris; by extension, an overwhelming victory in an election. Often used metaphorically in political contexts to describe a decisive margin of success.
The heavy rain caused a landslide that blocked the main road.
After the scandal was revealed, the opposition party won the local election in a landslide.
Geologists warned that the deforestation of the hillside had significantly increased the risk of a catastrophic landslide during the upcoming monsoon season.
From land + slide.
Often used with the preposition 'in' when referring to political victories ('won in a landslide').