acquiesce vs approve

acquiesce

verb
  • 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. 

  • To concur upon conviction; to assent to; usually, to concur, not heartily but so far as to forbear opposition. 

approve

verb
  • To consider worthy (to); to be pleased (with); to accept. 

  • To officially sanction; to ratify; to confirm; to set as satisfactory. 

  • To make profit of; to convert to one's own profit — said especially of waste or common land appropriated by the lord of the manor. 

  • To regard as good; to commend; to be pleased with; to think well of. 

How often have the words acquiesce and approve occurred in a corpus of books? (source: Google Ngram Viewer )