alarming (adj.)

• awing
• bad
• chilling
• critical
• dangerous
• daunting
• deterrent
• disconcerting
• discouraging
• disheartening
• dismaying
• disquieting
• explosive
• fearful
• fearsome
• frightening
• frightful
• menacing
• parlous
• perilous
• scary
• serious
• startling
• threatening
• ugly