Defection (noun)

1. The act of leaving a political party, religion, or loyalty for another one.
2. The act of deserting a duty or responsibility.

Origin:

Derived from the latin word 'defectio' meaning 'desertion'.

Examples:

1. The defection of the former general dealt a significant blow to the opposition party.
2. The defection of several key players from the team led to their loss in the championship game.
3. The defection of the senator to the opposition caused a major political upset.
4. The defection of the spy provided valuable information to the enemy.
5. The defection of several members of the religious group led to its decline.