Synonyms and Antonyms of formidable
- a formidable, irascible old man who frightened the neighborhood children
daunting, demoralizing, disconcerting, discouraging, dismaying, disquieting, distressing, disturbing, perturbing, startling, threatening, troubling, trying, unnerving
bone-chilling, creepy, eerie (also eery), weird
appalling, atrocious, awful, grisly, gruesome (also grewsome), hideous, horrid, macabre, monstrous, nightmarish
- running a marathon is a formidable undertaking
arduous, Augean, backbreaking, challenging, demanding, difficult, effortful, exacting, grueling (or gruelling), hard, heavy, hellacious, herculean, killer, laborious, moiling, murderous, pick-and-shovel, rigorous, rough, rugged, severe, stiff, strenuous, sweaty, tall, testing, toilsome, tough, uphill
abstract, abstruse, complex, complicated, elusive, hairy, insoluble, intricate, involved, knotty, opaque, problematic (also problematical), recondite, serious, spiny, stubborn, thorny, ticklish, tricky
bruising, burdensome, exhausting, labored, onerous, oppressive, stressful, taxing, tight, trying
annoying, bothersome, distressing, irksome, troublesome, vexatious
cheap, easy, effortless, facile, light, mindless, simple, soft, undemanding