Vigilant means keeping careful watch for danger. Not nervous — alert, and staying alert.
The word implies a duty as well as a state, which is why it belongs to guards, nurses and border officials, and why public warnings ask people to remain vigilant. It is stronger than watchful because it suggests the watching goes on and on. The noun is vigilance, and the related vigil is a long watch kept through the night. A vigilante is somebody who takes that watching too far and starts enforcing the law themselves.
1adjectivevigilantKeeping careful and continuous watch for possible danger.
“Staff were asked to stay vigilant over the weekend.”
Also accepted in games: watchful, alert
Vigilant is staying awake. Latin vigil meant awake and vigilāre to keep watch, which is the same vigil that is kept at a bedside.
Latin
vigilans
French
vigilant
English, today
vigilant
Built from
From French vigilant or its source, Latin vigilans, present participle of vigilare (“stay awake”), from vigil (“awake”). a doublet of vigilante, from Spanish. Displaced wacor.
Etymology from Wiktionary, CC BY-SA