knuckle under
US /ˈnʌk.l̩ ˌʌn.dər/
UK /ˈnʌk.l̩ ˌʌn.dər/

1.
someterse, ceder, doblegarse
to yield or submit to pressure or authority
:
•
After weeks of resistance, he finally had to knuckle under to their demands.
Después de semanas de resistencia, finalmente tuvo que someterse a sus demandas.
•
The company refused to knuckle under to the union's threats.
La empresa se negó a someterse a las amenazas del sindicato.