noun

careful and persistent work or effort.

few party members challenge his diligence as an MP

conscientiousness,assiduousness,assiduity,industriousness,rigour,rigorousness,punctiliousness,meticulousness,carefulness,thoroughness,sedulousness,attentiveness,heedfulness,earnestness,intentness,studiousness,constancy,perseverance,persistence,tenacity,pertinacity,zeal,zealousness,dedication,commitment,tirelessness,indefatigability,doggedness,industry,hard work,application,effort,concentration,care,attention,laboriousness,continuance,perseveration