Agents of character assassinations employ a mix of open and covert methods to achieve their goals, such as raising false accusations, planting and fostering rumours, and manipulating information.
It is an attempt to tarnish a person's reputation. It may involve exaggeration, misleading half-truths, or manipulation of facts to present an untrue picture of the targeted person.
Character assassination is dirty fighting, make no mistake about it. It can be cowardly (like anyone who bad-mouths you behind your back to friends or colleagues), or it can be in-your-face (like politicians who make no secret about their intent to wreck an opponent's reputation).