► 形容詞脆い  [(2)もろい]    
meaning:  fragile  rank: 2☆ 
建物は
地震で脆くも
崩れ
去った ⇨ The building collapsed easily by the earthquake
☆ 
彼は
精神的に脆い ⇨ He is mentally fragile
脆い  [(2)もろい]    
meaning:  susceptible  rank: 2☆ 
彼は
情に脆い ⇨ He is susceptible to emotions. He cannot stop helping people who need help
More examples:- 平和は脆い ⇨ Peace is fragile
 - うちの母は涙脆い ⇨ My mother cries a lot
 - セラミックは非常に硬い反面脆い ⇨ Ceramics are very hard while, even though, very brittle at the same time