To clear from alleged fault or guilt. (Merriam – Webster)
To remove blame from someone. (Cambridge Dictionary)
To clear from a charge of guilt or fault; free from blame; vindicate. (Dictionary.com)
To free from blame or guilt; vindicate or exonerate. (Collins Dictionary)
Show or declare that (someone) is not guilty of wrongdoing. (Oxford Dictionaries)
Criminal Responsibility and the Emotions: If Fear and Anger Can Exculpate, Why Not Compassion?