“Defamation” is an umbrella term, covering both libel and slander.
What’s the difference? Both concern the publication of defamatory material, however libel typically involves “lasting” forms of publication (in writing), such as print or online statements, whereas slander is more transient and includes spoken words or gestures.
The threshold for bringing a claim for defamation is a high one: the statement is not defamatory unless its publication has caused, or is likely to cause, “serious harm” to the reputation of the claimant.
For an individual, injury to feelings alone will not be sufficient: it will still be necessary to show serious harm to the person’s reputation.
In some cases the words used can be so damaging in themselves (for example to falsely accuse a teacher of being a paedophile) that serious harm can be inferred by the court without need for further evidence.
In the case of a “body that trades for profit” (for example, a company), it is not ‘serious harm’ unless it has caused, or is likely to cause, “serious financial loss”.
For an individual, a claim for defamation is a ‘personal action’, meaning only the person defamed may bring the claim.
It is also necessary to establish the publication by the defendant of the defamatory words (which may be easier with libel than slander), and the defamatory words must identify the claimant (which will be easier in some cases than others). Where identification is disputed, or where it’s unclear, it would have to be determined by the court.