forthright vs plain-speaking

forthright

adj
  • Markedly simple. 

  • Straightforward; not evasive; candid and direct. 

  • Fixed; settled; decided. 

  • Frank, outspoken. 

adv
  • Swiftly. 

  • At once, forthwith. 

  • Expressly, frankly, unhesitatingly. 

plain-speaking

adj
  • Synonym of plain-spoken 

How often have the words forthright and plain-speaking occurred in a corpus of books? (source: Google Ngram Viewer )