The defendant's appeal is dismissed.

1. Summary of grounds for appeal;

A. Although the defendant's act constitutes an element of defamation, the defendant's act constitutes a justifiable act that does not contravene the social norms, considering all circumstances such as the circumstances where the defendant made his/her speech, the contents of his/her speech, and the response of the victim before and after his/her speech.

B. The sentence imposed by the court below on the grounds of unreasonable sentencing (the fine of 500,000 won) is too unreasonable.

2. Determination

A. Determination of the misapprehension of legal principles as to the assertion of legal principles 1) An "act which does not violate social rules" under Article 20 of the Criminal Act refers to an act which is permissible in light of the overall legal order or the social ethics or social norms surrounding the act. Whether a certain act is justified as an act that does not violate social rules and thus, the illegality should be determined individually, under specific circumstances. The following elements are met: (i) legitimacy of the motive or purpose of the act; (ii) reasonableness of the means or method of the act; (iii) balance between the protected interests and the infringed interests; (iv) urgency; and (v) supplementaryness that there is no other means or method, other than the act (see, e.g., Supreme Court Decision 2010Do2680, May 27, 2010); (ii) circumstances acknowledged by the court below by lawfully adopting evidence; (iii) the defendant is a victim; and (iv) the victim's share in the victim's expression and the victim's reputation at the time of the act; and (iv) the victim's relation between the victim and the victim.