hobby horse vs interest

hobby horse

noun
  • A topic about which someone loves to talk at great length. 

  • A child's toy consisting of a (usually wooden or cloth) horse's head mounted on a stick. 

  • The Irish hobby, an extinct breed of horse. 

  • A puppet-like costume used in some traditional dances and festivals that gives its wearer the appearance of a man on horseback. 

  • An early bicycle with no pedals or brakes; a draisienne. 

interest

noun
  • A great attention and concern from someone or something; intellectual curiosity. 

  • An involvement, claim, right, share, stake in or link with a financial, business, or other undertaking or endeavor. 

  • The price paid for obtaining, or price received for providing, money or goods in a credit transaction, calculated as a fraction of the amount or value of what was borrowed. 

  • Condition or quality of exciting concern or being of importance. 

  • Any excess over and above an exact equivalent 

  • The persons interested in any particular business or measure, taken collectively. 

  • Something or someone one is interested in. 

  • Attention that is given to or received from someone or something. 

verb
  • To engage the attention of; to awaken interest in; to excite emotion or passion in, in behalf of a person or thing. 

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