Denial, in ordinary English usage, is asserting that a statement or allegation is not true. The same word, and also abnegation (German: Verneinung), is used for a psychological defense mechanism postulated by psychoanalyst Sigmund Freud, in which a person is faced with a fact that is too uncomfortable to accept and rejects it instead, insisting that it is not true despite what may be overwhelming evidence. An individual that exhibits such behavior is described as a denialist or true believer. Denial also could mean denying the happening of an event or the reliability of information, which can lead to a feeling of aloofness and to the ignoring of possibly beneficial information.
The subject may use:
simple denial: deny the reality of the unpleasant fact altogether
minimisation: admit the fact but deny its seriousness (a combination of denial and rationalization)
projection: admit both the fact and seriousness but deny responsibility by blaming somebody or something else