Ill not knuckle under till I have to, said Gilderman, savagely.
I'm not going to knuckle under to Louis and his beastly Jews—with a chance like that.
Whoever brings it in will have to knuckle under to Percival over its finance.
Come, Gildy, knuckle under and eat your humble-pie like a man.
On no account would he knuckle under, and debase his sacred profession.
"Oh, the kid will knuckle under, that's certain," snarled Bassett.
She just says that she'd rather die or go to prison than go back on her convictions and knuckle under to me.
If they think we're going to knuckle under to them they're very much mistaken.
Of course, he did, the mean pup; but never fear, I'll make him knuckle under.
We had to knuckle under the whole of the time, to the civil authorities.
mid-14c., knokel "finger joint; any joint of the body, especially a knobby one; morbid lump or swelling;" common Germanic (cf. Middle Low German knökel, Middle Dutch cnockel, German knöchel), literally "little bone," a diminutive of Proto-Germanic root *knuck- "bone" (cf. German Knochen "bone).
As a verb from 1740, originally in the game of marbles. To knuckle down "apply oneself earnestly" is 1864 in American English, extended from marbles (putting a knuckle on the ground in assuming the hand position preliminary to shooting); to knuckle under "submit, give in" is first recorded 1740, supposedly from the former more general sense of "knuckle" and here meaning "knee," hence "to kneel." The face-busting knuckle-duster is from 1858 (a duster was a type of protective coat worn by workmen).
knuckle knuck·le (nŭk'əl)
The prominence of the dorsal aspect of a joint of a finger, especially of one of the joints that connect the fingers to the hand.
A rounded protuberance formed by the bones in a joint.
A kink or loop of intestine, as in a hernia.
To yield; throw in the sponge: It's a shame she had to knuckle under to those bigots (1860+)