Synonyms of formidable

formidable

adjective

ˈfȯr-mə-də-bəl 

1

as in terrifying

causing fear

a formidable, irascible old man who frightened the neighborhood children

Synonyms & Similar Words

• terrifying
• frightening
• scary
• terrible
• horrible
• intimidating
• alarming
• dread
• fearful
• fearsome
• redoubtable
• shocking
• startling
• horrifying
• dreadful
• frightful
• eerie
• creepy
• ghastly
• dire
• forbidding
• horrendous
• direful
• gruesome
• threatening
• daunting
• troubling
• trying
• spine-chilling
• disturbing
• hair-raising
• unnerving
• discouraging
• perturbing
• hideous
• disconcerting
• disquieting
• demoralizing
• weird
• dismaying
• monstrous
• distressing
• nightmarish
• grisly
• appalling
• awful
• macabre
• horrid
• bone-chilling
• atrocious

Antonyms & Near Antonyms

• reassuring
• soothing
• comforting
• relaxing
• calming
• inviting
• tranquilizing
• consoling
• nonthreatening
• quieting
• lulling
• pacifying
• nonintimidating

2

as in difficult

requiring considerable physical or mental effort

running a marathon is a formidable undertaking

Synonyms & Similar Words

• difficult
• challenging
• tough
• rigorous
• hard
• demanding
• heavy
• complicated
• rugged
• herculean
• rough
• tall
• severe
• arduous
• strenuous
• murderous
• effortful
• sweaty
• killer
• laborious
• intricate
• complex
• exacting
• grueling
• exhausting
• uphill
• painful
• stiff
• testing
• serious
• backbreaking
• toilsome
• problematic
• elusive
• hellacious
• annoying
• stubborn
• grim
• tricky
• brutal
• thorny
• pick-and-shovel
• oppressive
• troublesome
• bruising
• Augean
• involved
• onerous
• tight
• insoluble
• stressful
• moiling
• hairy
• recondite
• abstract
• abstruse
• irksome
• burdensome
• knotty
• opaque
• ticklish
• spiny
• vexatious
• strict
• bothersome
• labored
• stringent
• cruel
• trying
• grievous
• taxing
• distressing
• inhuman

Antonyms & Near Antonyms

• easy
• simple
• soft
• light
• cheap
• effortless
• clear
• manageable
• facile
• uncomplicated
• undemanding
• achievable
• mindless
• elementary
• doable
• gentle
• smooth
• friendly
• soothing
• comforting
• relaxed
• accessible
• painless
• user-friendly
• idiotproof

Example Sentences

Recent Examples of formidable

The Eagles should run away with their district this season, although the Graham Steers are a formidable foe. — Charles Baggarly, Fort Worth Star-Telegram, 17 Sep. 2026

Her place playing the formidable Mrs Baxter is taken by Weaver, who has starred in the likes of Yellowstone, Picnic at Hanging Rock and Secret City down the years. — Jesse Whittock, Deadline, 17 Sep. 2026

Remaining on the job might even get harder, given that the proposal would expand the country’s already formidable child-care deserts. — Annie Lowrey, The Atlantic, 17 Sep. 2026

Selecting an outfit from Pathé’O’s many colors and styles is a formidable task. — Colette Davidson, Christian Science Monitor, 17 Sep. 2026