cockhead vs dirthead

cockhead

noun

  • Dickhead, a term of abuse. 

  • The glans penis. 

  • The rounded or pointed top of a grinding mill spindle, forming a pivot on which the stone is balanced. 

dirthead

noun

  • A term of abuse. 

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