保険【ほけん】
insurance, guarantee
危険【きけん】
danger, peril, hazard, risk
冒険【ぼうけん】
adventure, venture, venture which is unlikely to succeed, risky attempt, danger, hazard, risk
生命保険【せいめいほけん】
life insurance
険悪【けんあく】
dangerous, perilous, threatening, stormy, volatile, tense, critical, serious, stern (expression), hostile (attitude), sharp, harsh
険しい【けわしい】
precipitous, rugged, inaccessible, impregnable, steep, grim, severe, stern