Assiduous

assiduous \uh-SIJ-uh-wus\ adjective
: marked by careful unremitting attention or persistent application

Example sentence:
It's no surprise that my neighbor Jeanne's assiduous tending of her garden results in a good crop -- but you'd be surprised how well I do with my haphazardly tended plot.

Did you know?
Judges presiding over assizes (former periodical sessions of the superior courts in English counties) had to be assiduous in assessing how to best address their cases. Not only were their efforts invaluable, but they also served as a fine demonstration of the etymologies of "assiduous," "assess," and "assize." All three of those words derive from the Latin verb "assidere," which is variously translated as "to sit beside," "to take care of," or "to assist in the office of a judge." "Assidere," in turn, is a composite of the prefix "ad-" (in this case, meaning "near" or "adjacent to") and "sedere," meaning "to sit."