1. Careful watch or attention; readiness to see. Usually used with "for". Keep your eyes open for a boy in a red cap and sweater. The hunter had his eyes open for rabbits. They drove on with their eyes open for a gas station.
Synonym: EYE OUT, KEEP ONE'S EYES PEELED. 2. Full knowledge; especially of consequences; understanding of what will or might result. Used with "have" or "with". Automobile racing is dangerous. Bob went into it with his eyes open. Betty had her eyes open when she got married.
Antonym: CLOSE ONE'S EYES.