Definify.com
Webster 1913 Edition
Treacherous
Treach′er-ous
,Adj.
[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. Shakespeare
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
, Noun.