Character assassination is an attempt to tarnish [or destroy] a person’s reputation. It may involve exaggeration or manipulation of facts to present an untrue picture of the targeted person. It is a form of defamation and can be a form of ad hominem argument.*
The Irreversible Effects
For living individuals targeted by character assassination attempts, this may result in being rejected by his community, family, or members of his or her living or work environment. Such acts are often difficult to reverse or rectify, and the process is likened to a literal assassination of a human life. The damage sustained can last a lifetime or, for historical figures, for many centuries after their death.
Maliciously Deceptive Defamation
In practice, character assassination may involve doublespeak, spreading of rumors, innuendo or deliberate misinformation on topics relating to the subject’s morals, integrity, and reputation. It may involve spinning information that is technically true, but that is presented in a misleading manner or is presented without the necessary context. For example, it might be said that a person refused to pay any income tax during a specific year, without saying that no tax was actually owed due to the person having no income that year, or if a person was sacked from a firm, even though they may have been made redundant rather than actually fired. Source: Wikipedia.org
*in simple terms, an “ad hominem argument” is when someone attacks your character instead of the point you try to make.