conscientious

Concise Oxford English Dictionary © 2008 Oxford University Press:
conscientious /ˌkɒnʃɪˈɛnʃəs/

▶adjective

• 1 wishing to do what is right.

• 2 relating to a person's conscience.

– derivatives
conscientiously adverb,
conscientiousness noun.

– origin C17: from Fr. consciencieux, from med. L. conscientiosus, from L. conscientia (see conscience).