TRE'ACHER TREACHEROUS, adjective trech'erous. [See Treachery.] Violating allegiance of faith pledged; faithless; traitorous to the state or sovereign; perfidious in private life; betraying a trust. A man may be treacherous to his country, or treacherous to his friend, by violating his engagements or his faith pledged.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI