treachery
noun [ U ] formal uk/ˈtretʃ.ər.i/ us/ˈtretʃ.ɚ.i/
背叛，背信弃义
behaviour that deceives or is not loyal to someone who trusts you
From his cell on board ship, the captain wrote about the treachery of his crew. 在船上被关押的房间里，船长记录下了船员们的背叛行为。