Synonyms for Underhanded:

• adj.

  •deceitful (adjective)
  • clandestine,
  • covert,
  • crooked,
  • cunning,
  • devious,
  • dirty,
  • dishonest,
  • fraudulent,
  • furtive,
  • secret,
  • shady,
  • shifty,
  • sly,
  • sneaky,
  • surreptitious,
  • underhand,
  • unethical,
  • unfair,
  • unscrupulous,
  • wily,
  • shorthanded.
  •dishonest (adjective)
  • cheating,
  • corrupt,
  • crafty,
  • crooked,
  • deceitful,
  • devious,
  • dishonest,
  • dishonorable,
  • double-faced,
  • felonious,
  • fraudulent,
  • hypocritical,
  • immoral,
  • insincere,
  • traitorous,
  • treacherous,
  • turncoat,
  • unscrupulous,
  • untrustworthy,
  • Deceiving,
  • Prevaricating,
  • deceptive,
  • dirty.
  •improper (adjective)
  • undue.
  •secret (adjective)
  • cheating,
  • corrupt,
  • deceitful,
  • guileful,
  • scheming,
  • secretive,
  • backstairs,
  • sly.
  •shady (adjective)
  • shady.
  •underhand (adjective)
  • lubricious.
  •untruthful (adjective)
  • untruthful.

• n.

  •
  • classified,
  • confidential,
  • mysterious,
  • secret,
  • shadowy.
  •
  • disingenuous,
  • duplicitous,
  • guileful,
  • honest,
  • indirect,
  • lubricious,
  • shifty.
  •underhanded (noun)
  • corrupt,
  • crooked,
  • sneaky,
  • underarm,
  • underhand.

• Other synonyms:

  •
  • duplicitous,
  • false,
  • unreliable.
  •
  • guileful,
  • lubricious,
  • secret,
  • shifty.
  •
  • disingenuous,
  • indirect.
  •crafty
  • sly.
  •questionable
  • shady.
  •Other relevant words:
  • adroit,
  • amoral,
  • arch,
  • artful,
  • artificial,
  • astute,
  • back door,
  • backstairs,
  • bent,
  • calculating,
  • canny,
  • clandestine,
  • classified,
  • clever,
  • collusive,
  • confidential,
  • conniving,
  • conscienceless,
  • corrupted,
  • covert,
  • criminal,
  • cunning,
  • dark,
  • deceptive,
  • designing,
  • dirty,
  • dishonourable,
  • disingenuous,
  • disloyal,
  • dissembling,
  • doubtful,
  • dubious,
  • duplicitous,
  • evasive,
  • evil,
  • faithless,
  • false,
  • fast,
  • feline,
  • fishy,
  • foul,
  • foxy,
  • furtive,
  • guileful,
  • hole-and-corner,
  • hush-hush,
  • ill-gotten,
  • illicit,
  • indirect,
  • ingenious,
  • insidious,
  • intriguing,
  • janus-faced,
  • low-down,
  • lubricious,
  • lurking,
  • lying,
  • machiavellian,
  • mendacious,
  • mercenary,
  • mysterious,
  • nefarious,
  • oblique,
  • perfidious,
  • praetorian,
  • private,
  • privy,
  • questionable,
  • quiet,
  • rogue,
  • roguish,
  • rotten,
  • scheming,
  • secret,
  • secretive,
  • shadowy,
  • shady,
  • shameless,
  • sharp,
  • shifty,
  • shrewd,
  • sinister,
  • skulking,
  • slick,
  • slimy,
  • slippery,
  • sly,
  • sneak,
  • sneaking,
  • sneaky,
  • stealth,
  • stealthy,
  • subtle,
  • surreptitious,
  • suspicious,
  • tricky,
  • two-faced,
  • ulterior,
  • unconscientious,
  • unconscionable,
  • unctuous,
  • under-the-counter,
  • under-the-table,
  • underarm,
  • undercover,
  • underground,
  • underhand,
  • undermanned,
  • understaffed,
  • undue,
  • unethical,
  • unfair,
  • unobtrusive,
  • unprincipled,
  • unreliable,
  • unsavory,
  • untruthful,
  • venal,
  • vulpine,
  • wily,
  • Chiseling,
  • Double dealing,
  • False-hearted,
  • Plotting,
  • Slinking,
  • Slinky,
  • Trickish,
  • hugger mugger,
  • behind-the-scenes,
  • Covinous,
  • unexposed,
  • shorthanded,
  • finagling,
  • Ill-got,
  • Time-serving,
  • falsehearted,
  • ungenuine,
  • not kosher.

Antonyms for Underhanded:

• adj.

  • deceitful
    aboveboard, ethical, honest, open, public, scrupulous.
  • Other antonyms:
    aboveboard, acknowledged, avowed, clear, conscientious, decent, ethical, evident, forthright, honest, honorable, just, manifest, obvious, open, overarm, overhand, overhanded, overt, patent, plain, public, scrupulous, square, straight, straightforward, unclassified, unconcealed, undisguised, unrestricted, upright.