2
devil-may-care(adjective, madcap, feckless, unaccountable, irresponsive)
2
dishonest(adjective, bad, wrong, false, immoral)
2
fair-weather(adjective, dishonest, deceitful, unreliable, insecure)
2
faithless(adjective, false, dishonest, deceitful, unreliable)
2
fallible(adjective, unpredictable, unreliable, fickle, variable)
2
fanciful(adjective, light, weak, slight, imaginary)
2
feckless(adjective, madcap, unaccountable, irresponsive)
2
flighty(adjective, careless, immoral, thoughtless, reckless)
2
fly by night(adjective, unreliable, insecure, treacherous, incalculable)
2
flying
2
fragile(light, weak, slight, imaginary, flimsy)
2
frail(light, weak, slight, imaginary, flimsy)
2
hesitant(adjective, uncertain, nervous, doubtful, insecure)
2
inconsistent(adjective, loose, unpredictable, unreliable, variable)
2
infirm(adjective, light, weak, slight, imaginary)
2
irresolute(adjective, uncertain, nervous, doubtful, insecure)
2
makeshift(adjective, unpredictable, fickle, variable, spontaneous)
2
provisional
2
quick(adjective, transient, transitory, short-lived)
2
reckless(adjective, madcap, feckless, unaccountable, irresponsive)
10 years ago|3.8k views|share |citing 
APASmart Define. (2016). fly-by-night thesaurus. Retrieved September 28, 2026, from https://smartdefine.org/fly-by-night/thesaurus/synonyms
ChicagoSmart Define. 2016. "fly-by-night thesaurus" https://smartdefine.org/fly-by-night/thesaurus/synonyms (accessed September 28, 2026).
HarvardSmart Define 2016, fly-by-night thesaurus, Smart Define, viewed 28 September, 2026, <https://smartdefine.org/fly-by-night/thesaurus/synonyms>.
MLASmart Define. "fly-by-night thesaurus" 26 February 2016. Web. 28 September 2026. <https://smartdefine.org/fly-by-night/thesaurus/synonyms>