Treach"er*ous (?), a. [See Treacher.] 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.

The treacherous smile, a mask for secret hate.

Syn. -- Faithless; perfidious; traitorous; false; insidious; plotting.

-- Treach"er*ous*ly, adv. -- Treach"er*ous*ness, n.

Treach"er*ous (?), a. [See Treacher.] 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.

The treacherous smile, a mask for secret hate.

Syn. -- Faithless; perfidious; traitorous; false; insidious; plotting.

-- Treach"er*ous*ly, adv. -- Treach"er*ous*ness, n.

• Exhibiting treachery.
  
• Deceitful; inclined to betray.
  
• Unreliable; dangerous.
       a treacherous mountain trail