Other forms: nondisclosures
Nondisclosure is not sharing important information. If someone sells their house and doesn't tell the buyer that the basement floods every times it rains, that's nondisclosure.
Legally, nondisclosure means failing to reveal information that the law says you have to disclose. In a court case, attorneys must tell the opposing side basic details about the witnesses they plan to call. If they don't, they are guilty of nondisclosure. This word often appears in the phrase "nondisclosure agreement," which is a legal contract that guarantees the signer will keep certain information confidential — in other words, they promise not to disclose it.