lose heart vs wilt

lose heart

verb
  • To despair; to experience reduced morale. 

wilt

verb
  • To fatigue; to lose strength; to flag. 

  • To cause to fatigue; to exhaust. 

  • To droop or become limp and flaccid (as a dying leaf or flower). 

  • To cause to droop or become limp and flaccid (as a flower). 

noun
  • The act of wilting or the state of being wilted. 

  • Any of various plant diseases characterized by wilting. 

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