What does 'on thin ice' mean?

What it means: In a risky or precarious situation where one wrong move could lead to serious consequences.

"After that complaint, he's on thin ice with management."
"You're on thin ice asking for another extension."

The image: Walking on ice that might crack — every step is dangerous and could lead to a fall through. The danger is invisible until it's too late.

What it implies: The person has reached the edge of what's acceptable. Usually there's been previous behaviour or a situation that has used up goodwill or tolerance.

• "In a precarious position" — formal
• "Treading carefully" — implies awareness of the danger
• "On borrowed time" — slightly different — implies the end is inevitable
• "Walking a tightrope" — similar metaphor of delicate balance

Register: Casual to professional. Common when discussing someone's standing in a relationship or workplace.

Tags: idioms, risk, danger, workplace