dangerous ground
US /ˈdeɪn.dʒər.əs ɡraʊnd/
UK /ˈdeɪn.dʒər.əs ɡraʊnd/
1.
a situation or topic that is risky, controversial, or likely to cause trouble
:
•
Discussing politics at a family dinner can be dangerous ground.
•
He realized he was treading on dangerous ground when he questioned his boss's decision.