perfidement

== French == === Etymology === From perfide +‎ -ment. === Pronunciation === IPA(key): /pɛʁ.fid.mɑ̃/ === Adverb === perfidement treacherously, perfidiously === Further reading === “perfidement”, in Trésor de la langue française informatisé [Digitized Treasury of the French Language], 2012