underhand (adjective) underhand: deceitful
Sinonime: clandestine,
concealed,
crafty,
crooked,
cunning,
deceptive,
devious, dirty-dealing,
dishonest, dishonorable, double-crossing,
duplicitous,
fraudulent,
furtive, guileful, hush-hush,
indirect,
insidious,
oblique, on the QT, on the quiet,
secret,
secretive,
shady, shifty,
slippery*,
sly*, sneaking,
sneaky,
stealthy, sub-rosa,
surreptitious,
treacherous,
tricky, two-faced, two-timing, under wraps, undercover, underhanded,
unethical,
unfair,
unjust,
unscrupulous,
wilyAntonime: aboveboard,
forthright,
frank,
honest