Synonyms for Fly by night:

• adj.

  •dubious (adjective)
  • Mootable,
  • fly-by-night,
  • hesitant,
  • skeptical,
  • open,
  • debatable,
  • moot,
  • unconvinced,
  • unlikely,
  • problematic,
  • chancy,
  • arguable,
  • diffident,
  • fishy,
  • reluctant,
  • perplexed,
  • untrusty,
  • wavering,
  • suspect,
  • far-fetched,
  • disputable,
  • touch and go,
  • undecided,
  • equivocal,
  • indecisive,
  • uncertain,
  • suspicious,
  • iffy,
  • unclear,
  • improbable,
  • unassured,
  • dubitable.
  •fly-by-night (adjective)
  • momentary,
  • shifty,
  • disreputable,
  • unprofessional,
  • undependable,
  • impermanent,
  • temporary,
  • treacherous,
  • evanescent,
  • ephemeral,
  • untrustworthy,
  • irresponsible,
  • shady,
  • not to be relied upon,
  • not to be trusted,
  • Trustless,
  • slippery,
  • fleeting,
  • brief,
  • short-lived,
  • here-today-gone-tomorrow,
  • dubious,
  • passing,
  • unreliable,
  • cowboy,
  • questionable,
  • unsure,
  • slimy.
  •improvised (adjective)
  • offhand,
  • makeshift,
  • unstudied,
  • spur-of-the-moment,
  • ad-lib,
  • unprepared,
  • spontaneous,
  • unrehearsed,
  • extemporaneous,
  • hit-or-miss,
  • Improviso,
  • extempore,
  • impromptu,
  • Autoschediastic,
  • Extemporized,
  • band-aid.
  •insubstantial (adjective)
  • idle,
  • immaterial,
  • petty,
  • incorporeal,
  • feeble,
  • slight,
  • unsound,
  • thin,
  • false,
  • aerial,
  • fanciful,
  • fragile,
  • illusory,
  • infirm,
  • flimsy,
  • unsubstantial,
  • tenuous,
  • chimerical,
  • unreal,
  • intangible,
  • too little too late,
  • metaphysical,
  • decrepit,
  • puny,
  • slender,
  • airy,
  • frail,
  • poor,
  • imponderable.
  •irresponsible (adjective)
  • devil-may-care,
  • uncareful,
  • harebrained,
  • ill-considered,
  • immature,
  • unanswerable,
  • immoral,
  • incautious,
  • rash,
  • lax,
  • wild,
  • unstable,
  • capricious,
  • unpredictable,
  • flighty,
  • unaccountable,
  • thoughtless,
  • shiftless,
  • loose,
  • giddy,
  • carefree,
  • feckless,
  • fickle,
  • no-account,
  • scatterbrained.
  •Other relevant words: (adjective)
  • transitory.
  •shifty (adjective)
  • foxy,
  • devious,
  • shrewd,
  • elusive,
  • mendacious,
  • Unhonest,
  • evasive,
  • wily,
  • furtive,
  • lying,
  • slick,
  • cagey,
  • prevaricative,
  • untruthful,
  • Contriving,
  • sneaky,
  • insidious,
  • crafty,
  • cunning,
  • unprincipled,
  • Equivocating,
  • collusive,
  • fraudulent,
  • sly,
  • prevaricatory,
  • crooked,
  • scheming,
  • conniving,
  • tricky,
  • dodging,
  • dishonest,
  • duplicitous,
  • shuffling,
  • roguish,
  • underhand.
  •short-lived (adjective)
  • short,
  • short-term,
  • short-run,
  • over in a heartbeat,
  • short-haul,
  • of short duration,
  • gone in a heartbeat,
  • fugitive,
  • deciduous,
  • quick.
  •slippery (adjective)
  • mutable,
  • smooth,
  • slithery,
  • variable,
  • two-faced,
  • unsteady,
  • unsafe,
  • inconstant,
  • changeable,
  • insecure.
  •slipshod (adjective)
  • unthorough,
  • bedraggled,
  • slapdash,
  • unsystematic,
  • unmeticulous,
  • tacky,
  • slovenly,
  • disheveled,
  • botched,
  • shoddy,
  • threadbare,
  • raunchy,
  • inexact,
  • sloppy,
  • unkempt,
  • neglected,
  • untidy,
  • tattered,
  • junky,
  • scruffy,
  • messed-up,
  • faulty,
  • messy,
  • screwed-up,
  • imperfect,
  • scrubby,
  • haphazard,
  • fouled-up,
  • inaccurate,
  • shabby,
  • negligent.
  •transient/transitory (adjective)
  • moving,
  • volatile,
  • Migrating,
  • flying,
  • Transmigratory,
  • flash,
  • Flitting,
  • Emigrating,
  • Vacating,
  • insubstantial,
  • provisional,
  • going by.
  •transitory (adjective)
  • temporal,
  • transient,
  • fugacious.
  •treacherous (adjective)
  • misleading,
  • betraying,
  • deceptive,
  • traitorous,
  • two-timing,
  • perfidious,
  • snake in the grass,
  • unloyal,
  • catchy,
  • treasonable,
  • deceitful,
  • recreant,
  • double-crossing,
  • double-dealing,
  • unfaithful,
  • untrue,
  • False-hearted,
  • faithless.
  •undependable (adjective)
  • inconsistent,
  • no bargain,
  • bum,
  • indefinite,
  • trick,
  • indeterminate,
  • careless,
  • erratic,
  • no-good.
  •unethical (adjective)
  • flimflam,
  • dishonorable,
  • improper,
  • scam,
  • unscrupulous,
  • corrupt,
  • dirty,
  • wrong,
  • sharp,
  • unfair,
  • cheating,
  • mercenary,
  • illegal,
  • fake,
  • dirty-dealing.
  •unreliable (adjective)
  • implausible,
  • hollow,
  • sham,
  • mistaken,
  • vacillating,
  • pretended,
  • meretricious,
  • pseudo,
  • delusive,
  • fallible,
  • underhanded,
  • erroneous,
  • hallucinatory,
  • specious,
  • unconvincing,
  • weak.
  •unsure (adjective)
  • rootless,
  • mistrustful,
  • betwixt and between,
  • Fluctuant,
  • lacking,
  • distrustful,
  • wimpy,
  • wobbly,
  • shaky,
  • borderline,
  • in a quandary,
  • unconfident,
  • up for grabs,
  • irresolute.
  •untrustworthy (adjective)
  • fink,
  • fair-weather,
  • guileful,
  • disloyal.
  •vagabond (adjective)
  • mendicant,
  • nomadic,
  • straggling,
  • prodigal,
  • footloose,
  • wayfaring,
  • Strolling,
  • Roaming,
  • errant,
  • aimless,
  • fancy-free,
  • itinerate,
  • migratory,
  • rambling,
  • itinerant,
  • perambulatory,
  • wayward,
  • down-and-out,
  • Sauntering,
  • roving,
  • perambulant,
  • shifting,
  • drifting,
  • unsettled,
  • wandering,
  • destitute,
  • journeying,
  • travelling,
  • peripatetic.

• n.

  •fugitive (noun)
  • recluse,
  • waif,
  • dodger,
  • outcast,
  • hermit,
  • displaced person,
  • walkout,
  • exile,
  • vagabond,
  • truant,
  • stray,
  • deserter,
  • runaway,
  • Runagate,
  • derelict,
  • evacuee,
  • Bolter,
  • Escaper,
  • émigré,
  • refugee,
  • hunted person,
  • outlaw,
  • escapee.

Antonyms for Fly by night:

• adj.

  • dubious
    honest, positive, doubtless, probable, likely, definite, aboveboard, certain, clear, unquestionable, unambiguous, trusty, unobscure, undoubted, determined, Indubious, sure, believable, secure, Undoubtful.
  • fly-by-night
    long, trustworthy, dependable, permanent, responsible, reliable, enduring, lasting, reputable.
  • improvised
    planned, premediated, Rehearsed, designed.
  • insubstantial
    serious, substantial, strong, genuine, real, thick.
  • irresponsible
    careful, liable, accountable.
  • shifty
    frank, naive, forthright.
  • short-lived
    ethereal.
  • slippery
    harmless, stable, rough, coarse, dry, unslippery.
  • slipshod
    polished, well-done, refined, neat.
  • transient/transitory
    long-lasting, undying, incessant, persistent, neverending.
  • transitory
    long-lived, perpetual, lengthy.
  • treacherous
    true, untreacherous, loyal.
  • unethical
    ethical, correct, Uncorrupt, decent, principled, right, upright, suitable, appropriate, moral, good.
  • unreliable
    constant, steady, accurate, faithful, truthful.
  • unsure
    believing, unwavering.
  • untrustworthy
    open.
  • vagabond
    settled, Inhabiting, unmoving, fixed.