watchful
UK: ˈwɒtʃfəl | US: ˈwɑːtʃfəl
adj. alert and attentive to potential danger or difficulties
adj. characterized by vigilance or caution
The word "watchful" combines "watch," derived from Old English wæccan (to be awake, keep vigil), with the suffix "-ful," from Old English -full (full of). Originally, "watch" referred to staying awake for guard duty, later extending to general observation. The suffix "-ful" turns the verb into an adjective, meaning "full of watching." The term evolved to describe a state of careful attention, often implying readiness to act.
The watchful guard noticed the intruder immediately.
She kept a watchful eye on her toddler near the pool.
The teacher remained watchful for signs of cheating during the exam.
His watchful demeanor made him an excellent security officer.
The cat sat watchful at the window, waiting for birds.