名詞 fly-by-night:

1. a debtor who flees to avoid paying

形容詞 fly-by-night:

1. of businesses and businessmen of questionable honesty
   同義詞：shady
2. ephemeral

fly-by-night

adj.（形容詞）
Unreliable or unscrupulous, especially with regard to business dealings:
不負責任的，不可靠的：尤指在商業(yè)上不可靠的或缺德的：
例句：
.fly-by-night telephone companies that open up shop, sell some systems, then disappear when service is needed.(Mary Ellen Jordan)
.那些開店、賣貨、然后在你需要服務(wù)時跑得無影無蹤的不可靠的電話公司.(瑪麗·埃倫·喬丹)

Of an impermanent or insubstantial nature:
短暫的，一時的：有不長久或不實在特性的：
例句：
fly-by-night fashions in clothing.
時裝界變換無常的款式

n.also （名詞） 也作
fly-by-nighter
An unscrupulous or undependable person, especially one who leaves secretly without paying creditors.
無信譽的人，逃債的人：尤指那種不付款就偷偷離開的缺德或不可靠的人
Something of a shaky or impermanent nature.
一時興起之物：具有易動搖或暫時性的物品