loofah vs luffa

loofah

verb
  • To clean or scrub with a loofah. 

noun
  • Any bathing sponge 

  • A tropical vine, of the genus Luffa, having almost cylindrical fruit with a spongy, fibrous interior; the dishcloth gourd 

  • The dried fibrous interior used as a sponge for bathing 

luffa

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