fly-by-night vs mootable

fly-by-night

noun
  • A traveling businessman or tradesman. 

  • A creature which flies at night; a nocturnal flier or traveler. 

  • A person or business that appears and/or disappears rapidly, appearing untrustworthy, or giving an impression of transience. 

  • One who departs or flees at night in order to avoid creditors, law enforcement etc. 

mootable

adj
  • Capable of being mooted. 

How often have the words fly-by-night and mootable occurred in a corpus of books? (source: Google Ngram Viewer )