[ˈtrɛtʃ(ə)rəs], (Adjective)

Definitions:
- guilty of or involving betrayal or deception
(e.g: a treacherous Gestapo agent)

- (of ground, water, conditions, etc.) presenting hidden or unpredictable dangers
(e.g: a holidaymaker was swept away by treacherous currents)


Phrases:

Origin:
Middle English (in treacherous): from Old French trecherous, from trecheor ‘a cheat’, from trechier ‘to cheat’