[throw|cast|fling] caution to the [wind]

to start acting in a risky way without caring about its consequences

The idiom "throw caution to the wind" does not have a widely documented historical origin. It is considered an idiomatic expression that has evolved organically in the English language over time. It is used to describe a situation where someone decides to take a risk or act boldly,

Despite her normally cautious nature, she decided to throw caution to the wind and take a spontaneous trip around the world.
They flung caution to the wind and invested their life savings into the startup, hoping for a big return.
Castigating advice from friends, he flung caution to the wind and pursued his dream of becoming an actor.
When they won the lottery, they threw caution to the wind and splurged on a luxury vacation.
Sometimes, it's liberating to cast caution to the wind and embrace the thrill of the unknown in life's adventures.