go ahead vs pluck up

go ahead

verb
  • To proceed with; to begin. 

  • Used to grant permission for or to give endorsement of a suggestion or proposal. 

  • To send communication over the radio. 

pluck up

verb
  • To become more cheerful. 

  • To remove or acquire by plucking from, for example, the ground; to pick up. 

  • To summon positive emotion (especially courage); to muster. 

How often have the words go ahead and pluck up occurred in a corpus of books? (source: Google Ngram Viewer )