sedulous

adjective2

1. •
   Of a person: diligent in application or pursuit; constant and persevering in business or in endeavours to effect a goal; steadily industrious.

   • Since first this Subject for Heroic Song / Pleas'd me long choosing, and beginning late; / Not sedulous by Nature to indite / Warrs, hitherto the onely Argument / Heroic deem'd, [...] — 1667
2. •
   Of an activity: carried out with diligence.

   • He had much to learn about boys, and he learnt not by direct observation—for which he believed he was unfitted—but by sedulous imitation of the more experienced masters. — 1907