Defamation (also known as calumny, vilification, libel, slander or traducement) is the oral or written communication of a false statement about another that unjustly harms their reputation. Under common law, to constitute defamation, a claim must generally be false. Some common law jurisdictions also distinguish between spoken defamation, called slander, and defamation in other media such as printed words or images, called libel.
Now the definition of defamation is the action of damaging the good reputation of someone; slander or libel. The defense against defamation is truth.