[syn: awful, dire, direful, dread(a), dreaded, dreadful, fearful, fearsome, frightening, horrendous, horrific, terrible]
The Collaborative International Dictionary of English v.0.48:
Frighten \Fright"en\, v. t. [imp. Frightened; p. pr. & vb. n.
Frightening.] [See Fright, v. t.]
To disturb with fear; to throw into a state of alarm or
fright; to affright; to terrify.
More frightened than hurt. --Old Proverb.
Moby Thesaurus II by Grady Ward, 1.0:
41 Moby Thesaurus words for "frightening":
alarming, appalling, awing, browbeating, bulldozing, bullying,
chilling, cowing, daunting, demoralization, deterrent, deterring,
dire, disconcerting, discouraging, disheartening, dismaying,
disquieting, distressing, dreadful, fear-inspiring, fearful,
fearsome, formidable, frightful, hair-raising, harrowing,
hectoring, horrifying, intimidating, intimidation, overawing,
petrifying, psychological warfare, scaring, scary, shocking,
spooky, startling, terrifying, war of nerves