Antonyms of adj treacherous

2 senses of treacherous

Sense 1
treacherous, unreliable -- (dangerously unstable and unpredictable; "treacherous winding roads"; "an unreliable trestle")

INDIRECT (VIA dangerous) -> safe -- (free from danger or the risk of harm; "a safe trip"; "you will be safe here"; "a safe place"; "a safe bet")

Sense 2
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 treacherous

2 senses of treacherous

Sense 1
treacherous, unreliable -- (dangerously unstable and unpredictable; "treacherous winding roads"; "an unreliable trestle")
       => dangerous (vs. safe), unsafe -- (involving or causing danger or risk; liable to hurt or harm; "a dangerous criminal"; "a dangerous bridge"; "unemployment reached dangerous proportions")

Sense 2
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")