The park rangers remained vigilant throughout the dry season, watching for any sign of smoke that could signal a forest fire.
在整个旱季，公园护林员始终保持警惕，留意任何可能预示森林火灾的烟雾迹象。
Which choice best defines “vigilant”?
D — Watchful; alert; cautious. “vigilant” means watchful; alert; cautious.
Which word means “watchful; alert; cautious”?
A — vigilant. “vigilant” means watchful; alert; cautious.
vigilant — watchful; alert; cautious. In Chinese: 警惕的；警醒的.
vigilant is pronounced /ˈvɪdʒɪlənt/.
The park rangers remained vigilant throughout the dry season, watching for any sign of smoke that could signal a forest fire. (在整个旱季，公园护林员始终保持警惕，留意任何可能预示森林火灾的烟雾迹象。)
watchful, alert, attentive — all close in meaning to vigilant (watchful; alert; cautious).
careless, inattentive — each the opposite of vigilant (watchful; alert; cautious).
Yes. vigilant is on the SAT Prep Easy list — mid-frequency academic words that do get tested. The Digital SAT does not test vocabulary in isolation; words like this one are tested through Words in Context questions, where you choose the word that completes a passage most logically and precisely.
vigil (alertness) + ant→ watchful.