(1):
(v. i.) To rest satisfied, or apparently satisfied, or to rest without opposition and discontent (usually implying previous opposition or discontent); to accept or consent by silence or by omitting to object; - followed by in, formerly also by with and to.
(2):
(v. i.) To concur upon conviction; as, to acquiesce in an opinion; to assent to; usually, to concur, not heartily but so far as to forbear opposition.