frightful

1 causing fear a frightful sound emanated from somewhere deep within the forest Synonyms alarming, dire, direful, dread, dreadful, fearsome, forbidding, formidable, frightening, fearful, ghastly, hair-raising, horrendous, horrible, horrifying, intimidating, redoubtable, scary, shocking, spine-chilling, terrible, terrifyingRelated Words 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, nightmarishNear Antonyms calming, comforting, consoling, inviting, lulling, pacifying, quieting, reassuring, relaxing, soothing, tranquilizing (also tranquillizing); nonintimidating, nonthreatening

2 extremely disturbing or repellent I couldn't listen to the frightful details of the murder trial Synonyms appalling, atrocious, awful, dreadful, horrible, ghastly, grisly, gruesome (also grewsome), hideous, horrendous, horrid, horrific, horrifying, lurid, macabre, monstrous, nightmare, nightmarish, shocking, terrible, terrificRelated Words alarming, bloodcurdling, dire, direful, fearful, fearsome, forbidding, formidable, frightening, gut-wrenching, hair-raising, heart-stopping, intimidating, redoubtable, scary, terrifying; abhorrent, deplorable, disagreeable, disgusting, distasteful, loathsome, nauseating, noisome, obnoxious, obscene, offensive, repugnant, repulsive, revolting, sickening; abominable, evil, foul, heinous, noxious, odious, unspeakable, vile; grotesque, ugly, unsightlyNear Antonyms agreeable, appealing, attractive, delectable, delicious, delightful, enjoyable, enticing, inviting, pleasant, pleasing, pleasurable, satisfying, welcome; cheering, comforting, soothing

3 extreme in degree, power, or effect flew into a frightful fit of rage Synonyms acute, almighty, blistering, deep, dreadful, excruciating, explosive, exquisite, fearful, fearsome, ferocious, fierce, intense, furious, ghastly, hard, heavy, heavy-duty, hellacious, intensive, keen, profound, terrible, vehement, vicious, violentRelated Words accentuated, aggravated, concentrated, deepened; emphasized, enhanced, heightened, intensified, magnified; stressed; exhaustive, thorough; harsh, rigorous, severeNear Antonyms feeble, weak; shallow, superficial; moderated, qualified; alleviated, eased, lightened, toned (down); abated, decreased, diminished, lessened, reduced, subduedAntonyms light, moderate, soft