14
irresponsible(adjective, careless, foolish, dishonest, deceitful)
13
fleeting(adjective, short, unreliable, brief, shady)
13
untrustworthy(adjective, false, careless, foolish, uncertain)
12
fickle(adjective, careless, foolish, dishonest, immoral)
12
passing(adjective, unreliable, shady, transient, transitory)
12
temporary(adjective, short, unreliable, brief, shady)
11
ephemeral(adjective, light, weak, unreliable, brief)
11
fugitive(noun, adjective, person, short, brief)
11
short-lived(adjective, short, unreliable, brief, shady)
10
evanescent(adjective, short, unreliable, brief, shady)
10
impermanent(adjective, short, unreliable, brief, shady)
10
questionable(adjective, uncertain, dishonest, doubtful, deceitful)
10
undependable(adjective, false, careless, foolish, uncertain)
10
unreliable(adjective, false, careless, foolish, uncertain)
10
unsure(adjective, uncertain, nervous, dishonest, doubtful)
9
dubious(adjective, uncertain, nervous, dishonest, doubtful)
9
momentary(adjective, short, unreliable, brief, shady)
9
transient(adjective, moving, idle, unsettled, exile)
8
brief(adjective, short, unreliable, shady, temporary)
8
shady(adjective, bad, wrong, uncertain, dishonest)
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APASmart Define. (2016). fly-by-night thesaurus. Retrieved September 22, 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 22, 2026).
HarvardSmart Define 2016, fly-by-night thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/fly-by-night/thesaurus/synonyms>.
MLASmart Define. "fly-by-night thesaurus" 26 February 2016. Web. 22 September 2026. <https://smartdefine.org/fly-by-night/thesaurus/synonyms>