dil·i·gence 
 n. 1. Earnest and persistent application to an undertaking; steady effort; assiduity. 
2. Attentive care; heedfulness. 

1. (n.) Steady effort in pursuing an occupation:
    · application
    · assiduity
    · assiduousness
    · exertion
    · industriousness
    · industry
    · perseverance
    · persistence
    · sedulity
    · sedulousness
    · stick-to-it-iveness
    · laziness (antonym)
    · vacillation (antonym)

{The above is a sample definition as defined by The American Heritage Dictionary}