second string vs unequal

second string

adj
  • Not as good; of a lower quality or condition. 

noun
  • A unit of players which is considered to have a secondary level of talent and which usually plays after the first string. 

unequal

adj
  • Not the same. 

  • Out of balance. 

  • Inadequate; insufficiently capable or qualified. 

  • Erratic, inconsistent. 

noun
  • One who is not an equal. 

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