noun

Constant or close attention to what one is doing.

the assiduity with which he could wear down his opponents

persistence,pertinacity,determination,perseverance,doggedness,tenaciousness,single-mindedness,strength of will,firmness of purpose,strength of purpose,fixity of purpose,bulldog spirit,tirelessness,indefatigability,resolution,resoluteness,resolve,firmness,patience,purposefulness,staunchness,steadfastness,constancy,staying power,application,diligence,assiduity,sedulousness,insistence,relentlessness,inexorability,inexorableness,implacability,inflexibility