assiduity Play nounConstant or close attention to what one is doing. SYNONYMS applicationassiduitybulldog spiritconstancydeterminationdiligencedoggednessfirmnessfirmness of purposefixity of purposeimplacabilityindefatigabilityinexorabilityinexorablenessinflexibilityinsistencepatienceperseverancepersistencepertinacitypurposefulnessrelentlessnessresolutenessresolutionresolvesedulousnesssingle-mindednessstaunchnessstaying powersteadfastnessstrength of purposestrength of willtenaciousnesstirelessness