If something such as an action or an event underscores another, it draws attention to the other thing and emphasizes its importance.
例句
The Labor Department figures underscore the shaky state of the economic recovery...勞工部的數據進一步印證了經濟復蘇狀況的不穩定。The rash of accidental shootings underscores how difficult it will be to restore order here.一連串的意外槍擊事件凸顯了恢復該地區的秩序有多困難。
VERB
在（字詞、句子等）下畫線
If you underscore something such as a word or a sentence, you draw a line underneath it in order to make people notice it or give it extra importance.
例句
He heavily underscored his note to Shelley.他在給謝利的便條內容下面重重地畫了線。