In a manner that is extremely enthusiastic or excited. She danced crazily at the concert, not caring who was watching.
In a way that is not sensible or reasonable. He crazily decided to quit his job without having another one lined up.
In a manner that is erratic or unpredictable. The car swerved crazily down the road, causing other drivers to honk in alarm.
To an extreme degree; extremely. Housing prices have become crazily high in the city.