acquiescence

ot noun

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