|Noah Webster's Dictionary|
1. (a.) Governed by rules of right and wrong; -- said of a person.
2. (a.) Characterized by a regard to conscience; conformed to the dictates of conscience; -- said of actions.
Conscientious (1 Occurrence)
2 Chronicles 29:34 But the priests were too few, so that they could not flay all the burnt offerings: therefore their brothers the Levites helped them, until the work was ended, and until the priests had sanctified themselves; for the Levites were more upright in heart to sanctify themselves than the priests. (See NAS NIV)