/ˈprɪnsəpəl ɪn ðə fɜrst dɪˈɡriː/ – Phrase
Definition: thủ phạm chính, chính phạm.
A more thorough explanation: “Principal in the first degree” refers to a person who commits a crime directly or who is present at the scene and actively participates in the commission of the crime. This term is often used in criminal law to distinguish the main perpetrator or primary actor in a criminal act from others who may be involved in the crime in a secondary or accessory capacity.
Example: In criminal law, the principal in the first degree is the person who actually commits the crime, such as the individual who physically carries out a robbery.