treacherous Meaning, Definition & Usage

  1. adjective satellite dangerously unstable and unpredictable
    unreliable.
    • treacherous winding roads
    • an unreliable trestle
  2. adjective satellite tending to betray; especially having a treacherous character as attributed to the Carthaginians by the Romans
    punic; perfidious.
    • Punic faith
    • the perfidious Judas
    • the fiercest and most treacherous of foes
    • treacherous intrigues

WordNet

Treach"er*ous adjective
Etymology
See Treacher.
Definitions
  1. Like a traitor; involving treachery; violating allegiance or faith pledged; traitorous to the state or sovereign; perfidious in private life; betraying a trust; faithless.
    Loyal father of a treacherous son. Shak.
    The treacherous smile, a mask for secret hate. Cowper.
    Syn. -- Faithless; perfidious; traitorous; false; insidious; plotting. -- Treach"er*ous*ly, adv. -- Treach"er*ous*ness, n.

Webster 1913