​taking care to do things carefully and correctly. a conscientious student/teacher/worker; He was thorough and conscientious, rather than brilliant.

There are four meanings listed in OED's entry for the adjective conscientious, one of which is labelled obsolete, and one of which is considered derogatory.

noun /ˌkɒnʃiˈenʃəsnəs/ /ˌkɑːnʃiˈenʃəsnəs/ [uncountable] the quality of doing things carefully and correctly.

​in a careful and correct way. She performed all her duties conscientiously. Questions about grammar and vocabulary? Find the answers with Practical English ...

feeling a moral responsibility to do your work carefully and to be fair to others. She was a conscientious worker, and I'll miss her.

There are three meanings listed in OED's entry for the noun conscientiousness. See 'Meaning & use' for definitions, usage, and quotation evidence.

a person who refuses to serve in the armed forces for moral reasons. compare draft dodger, pacifist.

a person who refuses to serve in the armed forces for moral reasons compare draft dodger, pacifist. Want to learn more? Find out which words work together ...

Edited by: Tony Deverson and Graeme Kennedy ; Print Publication Date: 2005 ; Print ISBN-13: 9780195584516 ; Published online: 2005 ; Current Online Version: 2005.