This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

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adj. Closely observant or alert; vigilant: kept a watchful eye on the clock. See Synonyms at aware, careful.

adj. Archaic Not sleeping; awake.

adj. observant, vigilant and aware

adj. Full of watch; vigilant; attentive; careful to observe closely; observant; cautious; -- with of before the thing to be regulated or guarded; ; and with against before the thing to be avoided.

Wakeful; sleepless.

Vigilant; careful; wary; cautious; observant; alert; on the watch: with of before the thing to be regulated or observed, and against before the thing to be avoided: as, to be watchful of one's behavior; to be watchful against the growth of vicious habits.

Synonyms Watchful, Vigilant, Wakeful, attentive, heedful, circumspect, guarded. Wakeful refers to the lack of disposition to sleep, especially at times when one would ordinarily have such a disposition; watchful and vigilant refer to the mind, will, or conduct: they are of about equal vigor; watchful is the broader in its range of meaning.

adj. engaged in or accustomed to close observation

adj. experiencing or accompanied by sleeplessness

"MESSNER: No. He's doing what they call watchful waiting and he's doing fine."

vigilant    fly    wide-awake    Argus-eyed    heads-up    sleepless    lidless    wakeful    open-eyed    awake   

careless   

cautious    attentive    vigilant    heedful    circumspect    observant    wakeful    observing    alert    erect   

vigilant    attentive    wary    thoughtful    alert    cautious    anxious    shrewd    resolute    affectionate