adjective deliberately faithless; treacherous; deceitful: a perfidious lover.
Origin: 1590–1600; <
Latin perfidiōsus faithless, dishonest. See
perfidy,
-ous Related forms per·fid·i·ous·ly, adverb
per·fid·i·ous·ness, noun
un·per·fid·i·ous, adjective
un·per·fid·i·ous·ly, adverb
un·per·fid·i·ous·ness, noun
Synonyms
false, disloyal; unfaithful, traitorous.
Antonyms
faithful.