Heads-up and Open-eyed

Heads-up adjective - Fully alert and watchful.

Open-eyed and heads-up are semantically related. In some cases you can use "Open-eyed" instead an adjective phrase "Heads-up".

Open-eyed adjective - Paying close attention usually for the purpose of anticipating approaching danger or opportunity.

Heads-up and open-eyed are semantically related. Sometimes you can use "Heads-up" instead an adjective phrase "Open-eyed".