The Collaborative International Dictionary
knuckle under \knuc`kle un"der\, v. i. To yield; to submit; -- usually used with to.
Wiktionary
vb. (context intransitive idiomatic English) To yield or cooperate when pressured or forced to do so.
WordNet
v. consent reluctantly [syn: yield, give in, succumb, buckle under]
Usage examples of "knuckle under".
He slid a knuckle under her jaw and urged her chin up until she had to look at him.
And the best way to do this, to get you to knuckle under, is to weaken you by gettin’.
Even the Imperial lawyers had to knuckle under to ties of blood, eh?
I am always touched by the gallant audacity of a kitten, the fighting heart of a bantam cock, or the willingness of a little mart to die in his tracks rather than knuckle under.
He had put a knuckle under Doyle's chin and tilted the pale face up.
To have reached the point where he had to knuckle under to a tenth-rate knothead like Ed Schultz - it would have been better if he had never come out of the Valkyrie business.