acknowledge vs fess

acknowledge

verb
  • To admit the knowledge of; to recognize as a fact or truth; to declare one's belief in 

  • To own as genuine or valid; to assent to (a legal instrument) to give it validity; to avow or admit in legal form. 

  • To own or recognize in a particular quality, character or relationship; to admit the claims or authority of; to give recognition to. 

  • To be grateful of (e.g. a benefit or a favour) 

  • To report (the receipt of a message to its sender). 

fess

verb
  • To confess; to admit. 

adj
  • Of animals, bad-tempered, fierce. 

  • Lively; active; strong. 

  • Proud; conceited. 

noun
  • A horizontal band across the middle of the shield. 

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