Synonyms and related words :
alarming, awing, awkward, baffling, bewildering, bothering, chilling, confounding, confusing, crushing, daunting, defeating, deterrent, deterring, discomposing, discouraging, disheartening, dismaying, disquieting, distracting, disturbing, embarrassing, enigmatic, fear-inspiring, fearful, fearsome, frightening, frightful, frustrating, humiliating, intricate, mortifying, mysterious, mystifying, overawing, perplexing, perturbing, problematic, puzzling, scaring, scary, startling, unsettling, upsetting