Treacherously

The student treacherously cheated on the exam by using hidden notes.

The employee treacherously sabotaged his colleague's project to gain personal advantage.

The con artist treacherously swindled elderly individuals out of their life savings.

He treacherously embezzled funds from the company.

The hacker treacherously stole sensitive data from the company's servers.

The treacherously icy road caused several accidents.

The treacherously high waves prevented the fishermen from going out to sea.