Steady attention and effort, as to one's occupation: application, assiduity, diligence, industriousness, industry, sedulousness.

What is the meaning of assiduousness?

: showing great care, attention, and effort : marked by careful unremitting attention or persistent application assiduous planning an assiduous book collector She tended her garden with assiduous attention.

Is assiduousness a noun?

Conscientious and unremitting diligence.