Irish bull vs gibber

Irish bull

noun
  • A ludicrous, incongruent or logically absurd statement. 

gibber

noun
  • Gibberish, unintelligible speech. 

  • A balky horse. 

  • A stone or rock, of chalcedony or similar mineral, found strewn over arid regions of inland Australia; a gibber stone. 

verb
  • To jabber, talk rapidly and unintelligibly or incoherently. 

How often have the words Irish bull and gibber occurred in a corpus of books? (source: Google Ngram Viewer )