moldy vs mouldy

moldy

adj

  • Covered with mold. 

  • Stale or musty. 

mouldy

adj

  • Covered with mould. 

  • Worthless; lousy; rotten. 

  • Showing signs of neglect; disused. 

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