treacherous

adjectives

dangerously unstable and unpredictable
"treacherous winding roads"; "an unreliable trestle"
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"
is derived from
is derived from