precarious

affording no ease or reassurance

• “a precarious truce”

fraught with danger

• “dangerous waters”
• “a parlous journey on stormy seas”
• “a perilous voyage across the Atlantic in a small boat”
• “the precarious life of an undersea diver”
• “dangerous surgery followed by a touch-and-go recovery”

dangerously insecure

• “a precarious footing on the ladder”

not secure; beset with difficulties

• “a shaky marriage”