What to call the attitude of pursuing something

What will you call a person with an endless spirit of pursuing something?


Determined/resolute person:

Determination, resolution:

  • Firmness of purpose; resolve: approached the task with determination and energy.
  • A fixed intention or resolution: returned to school with a determination to finish.

also unyielding or tenacious :

  • Not bending; inflexible
  • Not giving way to pressure or persuasion; obdurate.

Source: www.thefreedictionary.com


The word Doggedness comes to my mind.

In some situations single-mindedly would also be useful.