Synonyms and related words :
Argus-eyed, advertent, agog, alert, all ears, all eyes, assiduous, attentive, aux aguets, aware, careful, cautious, chary, circumspect, concentrated, conscious, covering, custodial, defensive, diligent, eagle-eyed, earnest, finical, finicking, finicky, fostering, guarded, guardian, guarding, hawk-eyed, heedful, immunizing, intense, intent, intentive, keen-eyed, lidless, meticulous, mindful, nice, niggling, observant, observing, on guard, on the ball, on the job, on the lookout, on the watch, open-eared, open-eyed, openmouthed, parental, preventive, prompt, prophylactic, protecting, protective, prudent, quick, ready, regardful, safeguarding, screening, sharp-eyed, sheltering, shielding, sleepless, tutelary, unsleeping, vigilant, wakeful, wary, wide-awake, with open eyes