alike vs synonymous

alike

adj
  • Having resemblance or similitude; similar; without difference. 

adv
  • In the same manner, form, or degree; in common; equally. 

synonymous

adj
  • Having an identical meaning. 

  • Having a similar meaning. 

  • Such that both its forms yield the same sequenced protein. 

  • Of, or being a synonym. 

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