Thesaurus

Synonyms for Redoubtable include:

alarming, appalling, arrogant, atrocious, awful, baleful, beaming, big, bigheaded, bloodcurdling, boastful, braggart, bragging, braggy, chesty, chilling, cock-a-hoop, conceited, creepy, creepy-crawly, crowing, dignified, dire, direful, disdainful, dismaying, dread, dreaded, dreadful, egotistic, egotistical, fearful, fearsome, forbidding, formidable, frightening, frightful, ghastly, glorious, gratifying, grim, grisly, gruesome, hair-raising, hairy, haughty, horrendous, horrible, horrific, horrifying, house-proud, illustrious, immodest, lordly, macabre, menacing, minacious, minatory, nightmarish, ominous, overproud, persnickety, petrifying, pleased, prideful, proud, proud of, purse-proud, redoubtable, respected, scarey, scary, self-aggrandising, self-aggrandizing, self-conceited, self-important, self-respectful, self-respecting, shabby-genteel, shivery, shuddery, sick, sinister, sniffy, snooty, snot-nosed, snotty, stuck-up, stupefying, supercilious, swaggering, swelled, swollen, swollen-headed, terrible, terrific, terrifying, threatening, too big for one's breeches, ugly, unnerving, uppish, vain, vainglorious

redoubtable is a ADJ.