11 letters · 16 points in Scrabble
adjective dangerously unstable and unpredictable
adjective tending to betray; especially having a treacherous character as attributed to the Carthaginians by the Romans
originFrom Old French trecheros, tricheros (“deceitful”), equivalent to treacher + -ous. See treacher.
Etymology from Wiktionary, CC BY-SA 3.0