acquiescence

noun2

1. •
   A silent or passive assent or submission, or a submission with apparent consent, distinguished from avowed consent on the one hand, and on the other, from opposition or open discontent; quiet satisfaction.

   • She nodded in quiet acquiescence.
   • His acquiescence to their demands surprised everyone.
2. •
   Inaction, passivity, or neglect to take legal action when it is called for in order to assert, preserve, or safeguard a right, and which inaction implies the abandonment of said right.