What is Cover-up?

Legal Definition
A cover-up is an attempt, whether successful or not, to conceal evidence of wrongdoing, error, incompetence or other embarrassing information. In a passive cover-up, information is simply not provided; in an active cover-up, deception is used.

The expression is usually applied to people in positions of authority who abuse power to avoid or silence criticism or to deflect guilt of wrongdoing. Perpetrators of a cover-up (initiators or their allies) may be responsible for a misdeed, a breach of trust or duty, or a crime.

While the terms are often used interchangeably, cover-up involves withholding incriminatory evidence, while whitewash involves releasing misleading evidence. See also misprision.
-- Wikipedia
Legal Definition
This term is given to mean to hide a thing that is unlawful or to evade and impede investigations.