Smear campaign means an activity that can harm an individual’s reputation. It is an effort to destroy a targeted person’s image and character. It is a form of negative campaigning. Smear campaign is usually adopted by a rival political party or a candidate who intends to damage another political party or candidate’s reputation. Smear campaign is a tactic to bring down a person’s credibility.
For example, there were many smear campaigns against Obama during the 2008 presidential election.