Antonyms of adj perfidious

1 sense of perfidious

Sense 1
punic, perfidious, treacherous -- (tending to betray; especially having a treacherous character as attributed to the Carthaginians by the Romans; "Punic faith"; "the perfidious Judas"; "the fiercest and most treacherous of foes"; "treacherous intrigues")

INDIRECT (VIA unfaithful) -> faithful -- (steadfast in affection or allegiance; "years of faithful service"; "faithful employees"; "we do not doubt that England has a faithful patriot in the Lord Chancellor")

Similarity of adj perfidious

1 sense of perfidious

Sense 1
punic, perfidious, treacherous -- (tending to betray; especially having a treacherous character as attributed to the Carthaginians by the Romans; "Punic faith"; "the perfidious Judas"; "the fiercest and most treacherous of foes"; "treacherous intrigues")
       => unfaithful (vs. faithful) -- (not true to duty or obligation or promises; "an unfaithful lover")