• 危険きけん — danger
• 危機きき — crisis
• 危あぶない — dangerous
• 危あやうい — precarious; at risk
• 危害きがい — harm; injury
• 危機感ききかん — sense of danger; urgency

The character 危 originally depicted a person on a high, unstable structure — representing danger or instability. It’s common in signage and safety instructions and is closely associated with cautionary contexts.