- The definition of vigilant is watchful and alert.
An example of something vigilant is a guard dog.
vigilant definition by Webster's New World
Origin: French ; from Classical Latin vigilans, present participle of vigilare, to watch ; from vigil, awake: see vigil
- vigilantly adverb
vigilant definition by American Heritage Dictionary
Origin: Middle English, from Old French, from Latin vigilāns, vigilant-, present participle of vigilāre, to be watchful; see vigilante.
- vigˈi·lant·ly adverb