If someone is conscientious, that person strives to do what's right and to carry out his duties. Conscientious people show care and put in a big effort.
Being conscientious has to do with being careful, thoughtful, and decent. A conscientious doctor will do everything possible to help a patient. A conscientious teacher will spend extra time with students, just to make sure they're learning. A boss wishes every worker could be conscientious: it's a rare and wonderful trait. To be conscientious, you have to be willing to do the right thing even when it's difficult. Unfortunately, many people aren't conscientious.