unconventional vs unplain

unconventional

adj

  • Out of the ordinary 

  • Not adhering to convention or accepted standards 

  • Atypical 

noun

  • Something or someone that is unconventional. 

unplain

adj

  • Not plain. 

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