To beard the lion in his den
Definition 1 of 1
Pro Tip 1/3Boldness Implied
Using the phrase suggests courage in facing a difficult or intimidating situation. 
Despite the risk, she decided to beard the lion in its den by demanding fair treatment.
Pro Tip 2/3Power Dynamics
The phrase often reflects a situation where there's a clear power imbalance between parties. 
The journalist bearded the lion in its den when interviewing the corrupt politician.
Pro Tip 3/3Literal Misinterpretation
The 'lion' and 'den' are metaphorical for power, not real animals or places. 
He wasn't actually fighting animals; he bearded the lion in its den by challenging the board.