Libel and slander are both forms of defamation. The distinction is simple - libel claims involve written defamation, and slander claims are based something spoken. In order for a private person to establish a case for defamation, it must be established that the defendant either spoke or wrote defamatory language about the plaintiff, that there was publication of that language and damage to the plaintiff's reputation as a result of the defamation.
What constitutes defamatory language may be subjective, but the language must adversely affect one's reputation and be false. Therefore, even if the someone's reputation is harmed, if the language is truthful, there is no meritorious claim for defamation available.
As always, seek an experienced personal injury lawyer to discuss your particular case in greater detail.