His treacherous behaviour made them all feel anxious.
You can be every kind of treacherous thing at once!
It is just going to be a more treacherous road.
The President spoke of the treacherous intentions of the enemy.
treacherous road, sea, waters
Ice had made the roads treacherous.
a treacherous Gestapo agent / sexually transmitted diseases can be insidious and sometimes without symptoms
2. If the ground or sea is treacherous, it is extremely dangerous, especially because of bad weather conditions: Snow and ice have left many roads treacherous, and drivers are warned to use caution.
A man drowned while trying to rescue a friend struggling in the river's treacherous waters.
Yet, at the same time, the economic upturn in Europe is threatened by a particularly treacherousversion of globalisation, in the shape of financial markets without frontiers.