a bit lacking vs potty

a bit lacking

potty

verb
  • Synonym of go potty 

adj
  • Easy to pot the ball on. 

  • Insane. 

noun
  • A chamber pot, particularly (children) the pot used when toilet-training children. 

  • Any other device or place for urination or defecation: a toilet; a lavatory; a latrine; an outhouse. 

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