agree vs approve

agree

verb
  • To yield assent to; to approve. 

  • To make a stipulation by way of settling differences or determining a price; to exchange promises; to come to terms or to a common resolve; to promise. 

  • To consent to a contract or to an element of a contract. 

  • To be in harmony about an opinion, statement, or action; to have a consistent idea between two or more people. 

  • To suit or be adapted in its effects; to do well. 

  • To give assent; to accede 

  • To correspond to (another word) in a grammatical category, such as gender, number, case, or person. 

  • To resemble; to coincide; to correspond. 

approve

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

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

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