Strong-willed (adjective)

1. Having a strong determination or willpower.
2. Difficult to control or influence.
3. Having a strong and determined character.

Origin:

Compound word of strong and willed, it is a recent term, likely to have been formed in the last century.

Examples:

1. She was a strong-willed child who always stood up for what she believed in.
2. He was a strong-willed leader who never gave up on his goals.
3. The strong-willed horse was difficult to break.
4. The strong-willed employee refused to follow the company's rules.
5. The strong-willed athlete never gave up on the game.