under the knife

Idioms  

1. Undergoing surgery, as in He was awake the entire time he was under the knife. The phrase is often put as go under the knife meaning “be operated on,” as in When do you go under the knife? Knife standing for “surgery” was first recorded in 1880.

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Example Sentences

The larger-than-life footballer died of heart failure and acute pulmonary edema -- a condition where fluid accumulates in the lungs -- two weeks after going under the knife.

From Barron's • Apr. 23, 2026

Williams' cautiousness about going under the knife suggests he still has ambitions to continue on the baize for years to come - and who can blame him.

From BBC • Apr. 17, 2026

Patients who went under the knife late last year are now debuting tighter skin, flatter stomachs and lifted eyelids to their social networks.

From The Wall Street Journal • Feb. 7, 2026

Jackson continued her video by explaining she has no intentions to go under the knife to address the abnormality.

From Los Angeles Times • Nov. 11, 2025

Every day the storm delayed them, there was a greater chance that Maddy and Az had already gone under the knife.

From "Uglies" by Scott Westerfeld