butt-ugly vs plug-ugly

butt-ugly

adj

  • Extremely ugly. 

plug-ugly

adj

  • Very 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. 

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