1. with the head leading; head before the rest of the body
2. in a hasty, reckless, or impulsive manner

1. done with the head leading or in a reckless manner

Examples

• She dove headfirst into the swimming pool.
• The child slid headfirst down the playground slide.
• He jumped headfirst into the new business venture without proper planning.
• The company made a headfirst plunge into the competitive market.
• She fell headfirst off her bicycle onto the pavement.
• They rushed headfirst into marriage after knowing each other for only a month.
• The skier went headfirst down the steep slope.