Assiduous (adjective)

Diligent in one's application or attention; constantly or attentively occupied; unremitting; persistent.

Origin:

From the latin word "assiduus" meaning constant, frequent, or persistent.

Examples:

1. She was an assiduous student, always studying and getting good grades.
2. He was assiduous in his duties as a manager, never shirking his responsibilities.
3. The detective was assiduous in his efforts to solve the case.
4. Despite the setbacks, the company remained assiduous in its efforts to launch the new product.
5. The assiduous employee was recognized by the CEO for her hard work and dedication.