Defamation is categorised as felonious tort meaning thereby it is civil wrong as well as crime . One can take both the two actions at a time. Justification and fair or bonafide comment are both good defences against an action of defamation . But there is difference in between justification and fair or bonafide comment .

The difference may be shown in the following tabular form .

JustificationFair Comment
1.When the defendant takes a plea in an action for defamation that the words published are true , it is said justification .On the other hand , fair comment is a statement of opinion on the matters concerning public interest . Fair comment must not exceed the limits and must not be published maliciously .
2.Justification is concerning the facts and substance and not merely based on the belief of defendant.While fair and bonafide comment being a statement of opinion must be honest . If the facts are misstated , the defence of fair comment is of no avail. 
3.The defendant escapes the liability of defamation if the words are true whatever improper his motives may be . The defendant relies upon the truth of his assertion denying a claim of reputation which the plaintiff does not or ought not to possess.On the other hand , fair comment is used as a defence , if commented on public interest . Legitimate criticism is not a tort .