knuckle under

British  

verb

1. (intr, adverb) to give way under pressure or authority; yield

---

knuckle under Idioms  

1. Also, knuckle down. Give in, acknowledge defeat, as in The dean refused to knuckle under to the graduate students' demands, or He was forced to knuckle down before their threats of violence. Presumably this idiom alludes to a kneeling position with hands on the ground, knuckles down. [Mid-1700s]

---

Example Sentences

And man, that idea, that image of 22 public integrity lawyers locked in a room like truant children until they knuckle under, and somebody is going to file it.

From Slate • Feb. 14, 2025

Tesla recalled 21,599 China-made Model Ys in December, saying a suspension link may fall out of the steering knuckle under extreme stress conditions.

From Reuters • Feb. 17, 2022

Each, as it turned out, expected the other to knuckle under.

From Los Angeles Times • Aug. 3, 2021

Even when the masters of the universe knuckle under and hire good lawyers, they’re notorious for undermining them.

From Washington Post • Apr. 19, 2018

The distance from Rhode Island to New York was the same as the tip of my little finger to the first knuckle under it.

From "Chains" by Laurie Halse Anderson