watchful (adjective) watchful: on the lookout
Sinonime: alert, all ears,
attentive,
careful,
cautious, chary,
circumspect, glued,
guarded, heedful, hooked,
keen, not missing a trick,
observant, on guard, on one's toes, on the ball, on the job, on the qui vive, on the watch, open-eyed,
prepared,
ready, see after, see to,
suspicious, unsleeping,
vigilant, wakeful,
wary, wide-awake, with eyes peeled
Antonime: inattentive,
negligent