fly-by-night /ˈflaɪbaɪˌnaɪt/
  喜歡夜間外出的人,夜逃的負債者
  fly-by-night
       adj 1: of businesses and businessmen; "a fly-by-night operation"
              [syn: shady]
       2: of an impermanent nature; "the symphony is no fly-by-night
          venture"
       n : a debtor who flees to avoid paying