con ‧ fi ‧ den ‧ ti ‧ al ‧ i ‧ ty /ˌkɒnfədenʃiˈæləti, ˌkɒnfɪdenʃiˈæləti $ ˌkɑːn-/ BrE AmE noun [uncountable]
[ Word Family: noun : ↑ confidence , ↑ confidant , ↑ confidentiality ; adverb : ↑ confidently , ↑ confidentially ; adjective : ↑ confident , ↑ confidential ; verb : ↑ confide ]
a situation in which you trust someone not to tell secret or private information to anyone else:
The relationship between attorney and client is based on confidentiality.
breach of confidentiality (=when someone gives away information they have promised to keep secret)
It’s a breach of confidentiality for a priest to reveal what someone has said in the confessional.