Traitorous (adjective)

1. Having the characteristics of a traitor; treacherous.
2. Characterized by betrayal of allegiance or trust; treacherous.

Origin:

Traitor + -ous.

Examples:

1. The traitorous actions of the spy were uncovered.
2. The traitorous plot was foiled.
3. He was accused of traitorous behavior.
4. His traitorous actions were condemned by all.
5. The traitorous employee was fired.