Is this your crossword clue?
"alert" is also used as a crossword clue. If that's what you saw, the answer is often notification (12 letters).
Definitions
engaged in or accustomed to close observation
Word origin
From French alerte (“alert”), from the phrase à l'erte (“on the watch”), from Italian all'erta (“to the height”), from erta (“lookout, tower”).
Used in a sentence
“I saw an alert young fellow that cocked his hat upon a friend of his who entered just at the same time with myself”
“an airborne alert; ground alert”
Source: Wiktionary, CC BY-SA 4.0
Used as a crossword answer2 curated clues
01“Quick to notice danger”5 letters
02“Warning or watchful”5 letters
Not quite right?
"Search similar patterns."
A____