1. (n.) Constant or close application or attention, particularly to some business or enterprise; diligence.

2. (n.) Studied and persevering attention to a person; -- usually in the plural.

advertence advertency alertness application ardor assiduousness attention attention span attentiveness awareness bulldog tenacity care concentration consciousness consideration constancy diligence dogged perseverance doggedness ear earnestness endurance energeticalness energy engrossment fervor fidelity heed heedfulness indefatigability industriousness industry insistence insistency intentiveness intentness laboriousness loyalty mindfulness note notice observance observation obstinacy pains painstaking painstakingness patience patience of Job permanence perseverance persistence persistency pertinaciousness pertinacity plodding plugging preoccupation regard regardfulness relentlessness remark resolution respect sedulity sedulousness single-mindedness singleness of purpose slogging stability stamina staying power steadfastness steadiness stick-to-itiveness strenuousness stubbornness tenaciousness tenacity thoroughgoingness thoroughness thought tirelessness unremittingness unsparingness unswerving attention vehemence zealousness