strong-willed; volitional
Describes a person or attitude characterized by strong will, determination, or acting based on one's own volition.
He has a strong-willed personality and sees through whatever he decides to do.
Volitional action requires a clear sense of purpose.
意欲的 emphasizes eagerness and motivation, while 意志的 focuses on strength of will and determination.
意志 (will, volition) + 的 (adjectival suffix).