Treacherous
Pronunciation : Treach"er*ous
Part of Speech : a.
Etymology : [See Treacher.]
Definition : Defn: 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.
Source : Webster's Unabridged Dictionary, 1913