Synonyms of underhand in English:

underhand


See definition of underhand

adjective

1‘he was accused of employing underhand tactics’

SYNONYMS
deceitful, underhanded, dishonest, dishonourable, disreputable, unethical, unprincipled, immoral, unscrupulous, fraudulent, cheating, dubious, dirty, unfair, treacherous, duplicitous, double-dealing, below the belt, two-timing, two-faced, Janus-faced, unsporting, unsportsmanlike
devious, calculating, artful, crafty, cunning, conniving, scheming, designing, sly, wily, guileful, tricky
criminal, illegal, unlawful, nefarious
secret, secretive, clandestine, surreptitious, sneaky, sneaking, furtive, covert, veiled, shrouded, cloak-and-dagger, hugger-mugger, hole-and-corner, hidden, back-alley, backstairs, under the table, conspiratorial
North American snide, snidey
informal crooked, shady, bent, low-down, murky, fishy
British informal dodgy
Australian, New Zealand informal shonky
South African informal slim
ANTONYMS

honest, fair, above board