1) An act of deliberate betrayal 2) Back-stabbing 3) Betrayal 4) Betrayal of a trust 5) Deceit 6) Disloyalty 7) Duplicity 8) French word used in English 9) Lying 10) Perfidious business 11) Perfidiousness 12) Perfidy 13) SPECTRE specialty 14) Treason 15) Wilful betrayal 1) Bad faith 2) Betrayal 3) Deceit 4) Dishonesty 5) Disloyalty 6) Disobedience 7) Doubledealing 8) Infidelity 9) Perfidiousness 10) Perfidy 11) Sedition 12) Sellout 13) Traitory 14) Treason 15) Unfaithfulness 16) Wickedness 
Treachery is the betrayal or violation of trust. Treachery may also refer to: ...[law] Treachery is an offence in several countries. Both of the Australian and British offences were derived from or inspired by the related offence of treason. The name treachery was chosen because it is a synonym for treason. ==Australia== Treachery is a statutory offence in Australia. The offence is created by section 24AA of the Crimes ...
• (n.) Violation of allegiance or of faith and confidence; treasonable or perfidious conduct; perfidy; treason.
[n] - an act of deliberate betrayal
betrayal noun an act of deliberate betrayal
[SAT terms] an act of deliberate betrayal