Definition of "fly-by-night" []

• Unreliable or unscrupulous, especially with regard to business dealings: "fly-by-night telephone companies that open up shop, sell some systems, then disappear when service is needed” ( Mary Ellen Jordan). (adjective)
• Of an impermanent or insubstantial nature: fly-by-night fashions in clothing. (adjective)
• An unscrupulous or undependable person, especially one who leaves secretly without paying creditors. (noun)
• Something of a shaky or impermanent nature. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "In five essays loosely stitched together, Mr. Deb encounters, among others, a fly-by-night business-school operator in Delhi and a software engineer in Bangalore, impoverished peasants and factory workers in Andhra Pradesh, and a waitress at one of Delhi's upscale new restaurants."
• "Inside the FA, lots of progressive folk battle against entrenched empire builders whose reluctance to cede power makes Hosni Mubarak look like a fly-by-night."
• ""This is necessary in order to avoid fly-by-night, reckless and excitable flexing of muscles and decisions that overlook certain fundamentals that could irreparably harm the nerve-center of our recovering economy.""