The Collaborative International Dictionary
False-hearted
False-hearted \False"-heart`ed\, a.
Hollow or unsound at the core; treacherous; deceitful;
perfidious.
--Bacon. -- False"-heart`ed*ness, n.
--Bp.
Stillingfleet.
Wiktionary
false-hearted
a. disloyal, perfidious.
Usage examples of "false-hearted".
Yet if I betray my master's secret, I shall be a false-hearted knave and a traitor,- a crime provided for and punishable by military laws, as proved by the fact that twenty times in the wars I have seen miserable fellows strung up for doing in little degree what my scruples counsel me to do on a larger scale.