assiduous
/əˈsɪdʒuəs/
adjective
- Showing great care, attention, and effort; hardworking and diligent.
- His assiduous research over many years finally led to a major scientific breakthrough.
- The gardener was assiduous in watering each plant by hand, even during the hottest days.
- The assiduous student spent every evening reviewing her notes for the exam.