like the back end of a bus vs plug-ugly

like the back end of a bus

prep

  • Very unattractive. 

plug-ugly

noun

  • An ugly person. 

  • A member of an American nativist street gang that operated in the west side of Baltimore, Maryland, from 1854 to 1865. 

adj

  • Very ugly. 

How often have the words like the back end of a bus and plug-ugly occurred in a corpus of books? (source: Google Ngram Viewer )