Synonyms of formidable in English:

formidable


See definition of formidable

adjective

1‘every man wore a formidable curved dagger’

SYNONYMS
intimidating, forbidding, redoubtable, daunting, alarming, frightening, terrifying, petrifying, horrifying, chilling, disturbing, disquieting, dreadful, brooding, awesome, fearsome, ominous, foreboding, sinister, menacing, mean-looking, threatening, dangerous
informal spooky, scary, creepy
archaic direful, bodeful
ANTONYMS

pleasant-looking, comforting

2‘they face a formidable task’

SYNONYMS
onerous, arduous, taxing, difficult, hard, heavy, laborious, burdensome, strenuous, vigorous, back-breaking, stiff, uphill, relentless, Herculean, monumental, colossal
demanding, trying, tough, challenging, exacting, overwhelming
exhausting, wearying, fatiguing, tiring, punishing, gruelling, grinding
informal killing, no picnic
British informal knackering
rare toilsome, exigent
ANTONYMS

easy

3‘a formidable opponent’

SYNONYMS
capable, able, proficient, adept, adroit, accomplished
impressive, strong, powerful, mighty, terrific, tremendous, great, redoubtable, indomitable, invincible
seasoned, skilful, skilled, gifted, talented, masterly, virtuoso, expert, knowledgeable, qualified, trained
efficient, good, excellent, brilliant, outstanding, first-class, first-rate
informal mean, wicked, deadly, nifty, crack, ace, stellar, wizard, magic
North American informal crackerjack, badass
vulgar slang shit-hot
archaic, humorous compleat
rare habile
ANTONYMS

weak