(of ground, water, conditions, etc.) Hazardous because of presenting hidden or unpredictable dangers
a vacationer was swept away by treacherous currents
dangerously unstable and unpredictable; "treacherous winding roads"; "an unreliable trestle"
punic: tending to betray; especially having a treacherous character as attributed to the Carthaginians by the Romans; "Punic faith"; "the perfidious Judas"; "the fiercest and most treacherous of foes"; "treacherous intrigues"
(treacherously) faithlessly: in a disloyal and faithless manner; "he behaved treacherously"; "his wife played him false"
(treachery) perfidy: betrayal of a trust
(treachery) an act of deliberate betrayal
Betrayal (or backstabbing) is the breaking or violation of a presumptive social contract, trust, or confidence that produces moral and psychological conflict within a relationship amongst individuals, between organizations or between individuals and organizations. ...
Treachery is a statutory offence in Australia. There was also an unrelated statutory offence bearing that name in the United Kingdom, but it has been abolished. Both of these offences were derived from or inspired by the related offence of treason. ...
Exhibiting treachery; Deceitful; inclined to betray; Unreliable; dangerous
(treachery) Deliberate, often calculated, disregard for trust or faith; The act of violating the confidence of another, usually for personal gain; Treason
(adjective) - Marked by unforeseen hazards; dangerous or deceptive perilous hazardous risky
(adj.) deceptive, untrustworthy, or unreliable: "Treacherous daughters did not deserve to be mothers, and this was just punishment" (84).